Could Dark Fiber Light Up the Future?

Most of today’s data transporting are based on fiber optic network, which has faster speed and larger scale than ever before. However, needs for the data transporting capacity are still growing rapidly. The fiber optic network operators and providers usually lay more fiber optic cables than what is needed to avoid installing the fiber cables again and again, which also curbs the costs efficiently. These additional fiber cables are known as dark fiber or unlit fiber.

Dark fiber is optical fiber that has been installed and ready for use but is not currently being used, which has no electronics on either ends.

Dark fiber is primarily needed by operators taking into account the increasingly high demands of the end-user. Now the dark fiber can be leased or sold to individuals or companies who wants to create their own privately-operated optical fiber network rather than just leasing bandwidth or wants super fast speed and a highly secure network. The dark fiber network can be set up in a variety of ways, including dark fiber rings, point to point or point to multipoint.

dark-fiber

Benefits of Dark Fiber
  • Capacity: Dark fiber is a network of fiber optic cables that can carry high amounts of data at high speeds over hundreds of miles. Dark fiber also has unlimited expansion capability.
  • Flexible & Freedom: With dark fiber, the choice of network equipment would be more flexible. Individuals can choose the network equipment that supports the specific requirements.
  • Security: Fully dedicated, private physical network infrastructure.
Limits of Dark Fiber
  • Cost: the price for high performance dark fiber network is not low. Lighting up dark fiber requires maintenance and management. The time and equipment spent on lighting up the dark fiber is also an important part of the expense.
  • Location: Dark fiber networks are generally only available in the areas where fibers have already been installed which limits the application of dark fiber network. Dark fiber network is typically run between data centers and other places with existing fiber infrastructure.

As more and more individuals and companies look for platforms to improve internet bandwidth and data connectivity, dark fiber has become a popular topic. The performance of dark fiber is seductive. However, cost and limits of dark fiber should also be considered. There are many companies providing high performance dark fiber network, like Google whose price is very high. While the availability of WDM reduced the demand for fiber optic, which lower the price of dark fiber in some extend. The future of dark fiber is still in arguing and discussing.

Fiber Optic Cleaning – Fight Against Dust

Fiber optic connectors are very sensitive to contaminants like dust, oil and other dirt which can have great impact on the overall optical network, and can reduce its performance and maximum distance. Dust as small as 1 µm can have a noticeable effect on the connector’s attenuation (in excess of 0.5dB). Thus, fiber optic cleaning is one of the most basic procedures to main the operation of optical network system. It’s no exaggeration to say that cleaning consideration is the number one issue in fiber optic cable technology today.

Dust Is Everywhere

It seems that the dust, one of the biggest enemy in the fiber optic communication system, can always find its way to reach the fiber optic connector interface. When a fiber optic connector is mated or unmated, both the plug and receptacle might be polluted by the dust, oil from our fingers or other contaminants. The oil can leave a noticeable defect on the interface of the fiber optic connector, the oil also tends to trap dust against the fiber. To maintain the well operation of optical network, many fiber optic cleaning products and methods are being invented to fight again contaminants like dust.

Tips on Fiber Optic Cleaning

There are two main methods of cleaning based on the material used to clean the fiber optic. One is known as dry clean which is optic cleaning without using any solvent, the other is wet clean during which solvent, usually IPA (isopropyl alcohol) is used. Sometimes, the two methods should be combined. The following picture shows the suggested cleaning approach.

fiber optic cleaning process

The following are some tips which might be useful during fiber optic cleaning:

  • Both sides of the connectors should be cleaned, as dirt might be transferred from one to the other.
  • Keep dust caps on the connector, but do remember to verify that the dust caps are clean.
  • Do not just clean the end-face. The body of the connector ferrule should also be cleaned.
  • Do the cleaning in a clean, low-dust environment
  • You should not touch any transmissive or reflective surface of your optic and never reuse a lens tissue.

With proper handling and cleaning of your fiber optic, you can prevent damage and ensure their continued performance.

EDFA Selection Guide

An EDFA is an optical amplifier based on Erbium-doped optical fiber, that amplifies optical signals without converting them into electrical form. EDFAs use semiconductor lasers to pump Erbium Doped Fiber to amplify light in 1.5 μm wavelength region where telecom fibers have their loss minimum. It has low noise and can amplify many wavelengths simultaneously, which makes DWDM network possible and becomes a key enabling technology for optical communication networks. Since the realization of EDFA, it has developed rapidly and has become the amplifier choice for most applications in optical communication.

Basic of EDFA

The structure and working principle of an EDFA are simple. EDFA consists of a glass optical fiber doped with Erbium ions, WDM coupler, isolators, optical filter and pumping supply.EDFA

The picture above shows how an EDFA works. When a beam of light that carrying signals passes the Erbium-doped optical fiber, a pump laser provides the amplifier energy at Erbium absorption peaks of 980 and 1480 nm, through the use of WDM couplers. Then an optical filter removes the remaining traces of the pump beam so that it doesn’t interfere with reception of the signal. Isolators are inserted into the amplifiers to minimize the reflections on the EDFA

How to Choose the Right EDFA

First of all, you should make sure the network type in which you need to use EDFA. Depending on the network application, EDFA are generally designed into the following types:

  • DWDM EDFA: for this type of network, EDFA needs to be not only high power low noise, but also gain flattened such that all wavelength channels can be amplified equally.
  • SDH EDFA: For SDH network, EDFA design should allow maximum power budget to achieve the highest detection sensitivity.
  • CATV EDFA: There is also EDFA designed for CATV application, which has low noise with heat dissipation and ventilation in mind to ensure a long operation life.

The way in which EDFA used is to enhance the performance of optical data links is also important in selecting EDFAs. Depending on this, three types of EDFAs can be found in the market:

  • Booster EDFA: this EDFA is used to increase the optical output of an optical transmitter just before the signal enters an optical fiber.
  • Inline EDFA: as the optical signal is attenuated as it travels in the optical fiber. The inline amplifier is used to restore the optical signal to its original power level.
  • EDF pre-amplifier: this kind of EDFA is used at the end of the optical link in order to increase the sensitivity of an optical receiver.

Some other important elements should be considered before selecting EDFAs.

  • Wavelengths: you should make certain how many wavelengths will go through the EDFA and the beginning and ending wavelengths, for example 1530 to 1562 nm. For single wavelength link, you should know clearly the exact wavelength.
  • Power or loss budget: the budget tells us how much amplification you require for the whole link.
  • The location of EDFAs: After the transmitter, before the receiver, or in the mid-span.

Fiberstore DWDM EDFASelecting the right EDFA seems not an easy thing. However, if you are not sure about the types and numbers of EDFAs, you can visit FS which supplies various EDFAs with high quality and low price, as well as free EDFA solutions meeting customers’ requests.

Do Not Miss FS’s 40-Channel DWDM Multiplexer/Demultiplexer with the Lowest Price

DWDM (Dense Wavelength Division Multiplexing), an ideal optical multiplexing technology for long-haul data transporting, can put multiple channels of information using individual wavelength on the same fiber and increase the transmission capacity of optical networks considerably. Currently, DWDM technology is being widely applied in telecommunication networks and becomes the choice of many telecommunication operators.

Since the start of DWDM, various equipment and technologies have been used to enhance the high performance of every part of DWDM network. DWDM Multiplexer and demultiplexer are the main equipment that takes charge of the data sources’ multiplexing and demultiplexing. In the past years, DWDM multiplexers and demultiplexers have been upgraded rapidly to overcome the insertion loss and to meet the demands of the increasing requests for faster telecommunication, and they are always being combined in one rack by today’s vendors also known as DWDM Mux/Demux.

FS as a serious manufacture of optical communication published a 40-channel Duplex DWDM Athermal AWG Mux/Demux with competitive features which are described as following.

Fiberstore 40-channel DWDM Mux/Demux

Low Insertion Loss: Insertion loss is an inevitable problem in optical networks. Combining LC/UPC connectors of high quality and AWG technology, this duplex Mux/Demux reduces the insertion loss to a minimum of 3dB and increases the transmission capacity effectively.

Athermal AWG Technology: With athermal design this mux/demux device is temperature-intensive and allows multiplexing and demultiplexing of DWDM signals over a wide operating temperature range with long-term stability, reliability and large transmission capacity.

Large Channel Number & Excellent Channel Isolation: This DWDM Mux/Demux is designed for use within the C-band release of DWDM system which uses 40 channels at 100GHz spacing containing the channels from C21 (wavelength: 1560.606 nm) to C60 (wavelength: 1529.553 nm). Also 1.6nm (200 GHz) are available on request. Excellent channel isolation that eases the fiber handling is also provided.

Space-saving: With a standard 19-inch rack mount housing size, this DWDM Mux/Demux saves space effectively.

High quality and Inexpensive: The products of FS has been appreciated by customers for its reliable quality. Comparing with other manufactures, FS offers the lowest price for such a high quality 40-channel DWDM Mux/Demux.

40-Channel DWDM Mux/Demux

For detailed specifications of this low insertion loss 40-channel Duplex DWDM Athermal AWG Mux/Demux with Monitor Port, please visit FS’s online shop. FS currently has 10 of this DWDM Mux/Demux in stock and can deliver on the same day of ordering. FS also provides a custom package to meet customers’ requirements.

Some Common Fiber Optical Transceiver

Fiber optic transceiver including both transmitter and receiver in a single module is an important equipment transmitting and receiving data to support the normal operation of optical fiber data transmission system. The market currently offers a wide selection of fiber optic transceiver for use with different types of wire, fiber and wavelength and so on.

A group of companies joined together to agree on package standards also called multisource agreements (MSAs). The package standards help customers choose the best transceivers to their applications and make sure the they can use transceiver from multiple vendor without redesigning the board. In the following text, some common fiber optic transceivers according to package standards are introduced in details.

9-PIN&GBIC&SFF
9-Pin transceiver
 is also known as 1×9 optical transceiver. This transceiver has a single row of output pins at the rear of the device. The optical interface is usually ST or duplex SC receptacles. It is mainly used in fiber optic transceiver, optical switches, single/multi-mode converter as well as some industrial control applications.

GBIC transceiver, namely gigabit interface converter transceiver, is a plug-in interface designed to allow a pluggable interface for Gigabit Ethernet. It offers a standard, hot swappable electrical interface and can support a wide range of physical media from copper to long-wave single mode optical fiber, at lengths of hundreds of kilometers. However, this type of transceiver is gradually replaced by SFP transceiver which has more advantages.

SFF (small form-factor) transceiver is a compact optical transceiver used in optical communications for both telecommunication and data communications applications. Compare to 9-pin and GBIC transceivers, SFF transceivers is smaller allowing more ports in a given area. SFF transceivers have 10 or 20 I/O (input/output) pins that solder to the board.

SFP&SFP+&XFPSFP transceiver, small form-factor pluggable, small hot-pluggable optical module is a pluggable version of SFF transceiver and an upgraded version of the early GBIC module, with 10 I/O connections at the rear of the package. With smaller volume and higher integration, it is currently the most popular fiber optic transceiver.

SFP+ transceiver, also called enhanced SFP or SFP plus, with a higher transmission rate usually up to 8.5 G or 10 G, is a kind of optical transceiver module specified for 8Gbps/10Gbps/16Gbps fiber channel and 10Gigabit Ethernet applications.

XFP transceiver, 10Gigabit small form-factor pluggable transceiver, is the next generation SFP transceiver for 10Gbps application. This type of transceiver is hot-swappable and protocol-independent and is usually used to 10Gbps SONET/SDH, fiber channel, Gigabit Ethernet and other applications, but also of CWDM DWDM link.

X2&XENPAKXENPAK transceiver is a pluggable transceiver for 10Gbps applications, specifically 10 Gigabit Ethernet. The electrical interface is called XAUI, which provides four 2.5Gbps signals to the transmitter, which multiplexes or serialize them into a single 10Gbps signal to drive the source. It uses a 70-pin electrical connector. The optical interface is usually a duplex SC.

X2 transceiver is based on the XENPAK transceiver standards. It is shorter than XENPAK transceiver but uses same 70-position electrical and duplex SC interfaces. Unlike XENPAK, X2 devices mount on top of the board and are low enough to allow boards to be stacked side by side.

Introduction of Fiber Optic Sensor

Optical fibers are mainly applied in telecommunications, which has significantly changed this industry. However, there is also a growing application of optical fibers in sensing applications for measurement. Many components associated with optical fibers are developed to sensing applications. One of the most significant components—fiber optic sensor (also known as optical fiber sensor) is now being widely used in sensing applications.

Fiber optic sensors are fiber-based devices to sense some quantities like temperature, pressure, vibrations, displacement, rotations or concentration of chemical species. The basic instrumentation required for sensor are optical source (often a single-frequency fiber laser), sensing element, optical detector and end-prossesing devices (optical-spectrum analyzer, oscilloscope). A block diagram of fiber optic sensor is showed in the following picture.

8-30-2014-10-06-53-AM

Fiber optic sensor offers a wide range of advantages, which makes it being applied in many field successfully. Its advantages are as following.

  • Explosion proof: In fiber optic sensor, the primary signal is an optical. Therefore, there is no risk of spark or fiber.
  • Immunity to electromagnetic interference: Since the fibers are composed of dielectric such as glass. The fiber optic sensor is immune to radio frequency and electromagnetic.
  • Small size, light weight and flexible: This feature extends the applications of fiber optic sensor to many fields, like aircraft.
  • High sensitivity: The optical fiber sensors are highly sensitive and have large bandwidth. When multiplexed into arrays of sensors the large bandwidths of optical fibers themselves offer distinct advantages in their ability to transport the resultant data.
  • Remote sensing: With the availability of low loss optical fibers, the optical signal can be transmitted up to a long distance transmitted up to a long distance (10-1000m). Thus the remote sensing is possible with the optical fiber.
  • Environmental ruggedness and resistant: The optical fiber are manufactured from non-rusting materials such as plastics or glasses, therefore, the fibers have excellent stability when in permanent contact with electrolyte solutions, ionizing radiation etc. Further the fibers can withstand high temperature as high as 350 ca. Special fibers can extend sensor operation beyond 350c to as high as 1200c.
  • Compactness: With the availability of solid-state configurations (small size sources and detectors) it is possible to design a compact optical fiber sensor system.

Based on the sensor location, the fiber optic sensors are generally classified into two types, namely intrinsic and extrinsic fiber optic sensor.

Intrinsic fiber optic sensor can provide distributed sensing over very large distances, which is the most useful feature of it. In intrinsic fiber optic sensor, sensing takes place within the fiber itself. Only a simple source and detector are required. This sensor depends on the properties of the optical fiber itself to convert an environmental action into a modulation of the light beam passing through it. The basic concept of the intrinsic fiber optic sensor is showed in the picture below.

Intrinsic fiber optic sensor

Extrinsic fiber optic sensors use an optical fiber cable, normally a multimode one, to transmit modulated light from either a non-fiber optical sensor, or an electronic sensor connected to an optical transmitter. In this sensor, the fiber may be used as information carriers that show the way to a black box. It generates a light signal depending on the information arrived at the black box. The black box may be made of mirrors, gas or any other mechanisms that generates an optical signal. These sensors are used to measure rotation, vibration velocity, displacement, twisting, torque and acceleration. The major benefit of these sensors is their ability to reach places which are otherwise unreachable. The best example of this sensor is the inside temperature measurement of the aircraft jet engine. The following picture shows the basic concept of the extrinsic fiber optic sensor.

Extrinsic fiber optic sensors

Fiberstore offers fiber optic sensors of high quality. For more information about fiber optic sensor, you can visit its online shop.

Basic of PON

PON, namely, Passive Optical Network, is a telecommunications network that uses ponit-to-multipoint fiber to the premises in which unpowered optical splitters are used to enable a single optical fiber to serve multiple premises. It is an optical-fiber-based network architecture that can provide much higher bandwidth in the access network compared with traditional copper-based networks and is regarded as an ideal solution to last-mile bandwidth bottlenecks. Some of the most primary PON parts and their functions will be introduced in the rest of this article.

Passive optical network

PON consists of an Optical Line Termination (OLT) at the service provider’s Central Office (CO), a number of Optical Network Units (ONUs) and Optical Network Terminals (ONTs) near end users and Optical Distribution Network (ODN) within which optical fibers, fiber optic connectors, passive optical splitters, and auxiliary components collaborate with each other. The above picture shows passive optical network system applied in FTTH/FTTB/FTTC/FTTCab.

OLT is located at the CO. Its main function is to control the information float across the ODN, going both directions. OLT has two float directions: one is upstream getting an distributing different type of data and voice traffic from users, the other is downstream getting data, voice and video traffic from metro network or from a long-haul network and sending it to all ONT modules on the ODN.

Fiberstore EPON ONU with 1-PON Port and 8 10100M ports  Fiberstore OLT with 8-PON Ports

ONT and ONU are basically the same device. ONT is at the customer’s premises to use optical fiber for connecting to the PON on the one side, while interfacing with customers on the other side. ONU receives optical signal and converts it into an electrical signal. However, it is located outside the home, working in different temperature and weather conditions. Thus, ONU should resist water, winds and vandals. There should be an emergency battery backup in ONU in case that the power is off.

ODN containing optical fibers, fiber optic connectors, passive optical splitters, and auxiliary components, is an indispensable path for transmitting PON data and directly affects the performance, reliability, and scalability of a PON system.

Splitter Singlemode Dual Window 250µm Bare Fiber SplitterFiberstore ONT with 2 pots and wifi

The passive optical splitter or PON splitter in ODN is the main part of PON being passive. With a single PON splitter taking one input cable, 32 or 64 subscribers can be served at the same time. In PON the splitters can be arranged in star, ring or tree configurations to increase reliability. There are mainly two kinds of passive optical splitters: one is the traditional fused type splitter as known as FBT coupler or FBT WDM optical splitter, which features competitive price; the other is the PLC splitter based on the PLC (Planar Lightwave Circuit) technology, which has a compact size and suits for density applications.

Fiberstore PON Solution

The mentioned components are the basic parts of PON.  Fiberstore focusing on optical communication for more than 14 years in both technology and manufacturing, can offer perfect PON solution according to customers’ needs. All the mentioned components can be found in the online store of Fiberstore, including but not limited to: OLT, ONT, ONU, splitter, optical fiber and connectors.

7 Factors to Consider before Selecting An OTDR

An OTDR (Optical Time Domain Reflectometer) is a fiber optic tester for the characterization of optical networks that support telecommunications. The purpose of an OTDR is to detect, locate, and measure elements at any location on a fiber optic link. An OTDR needs access to only one end of the link and acts like a one -dimensional radar system. By providing pictorial trace signature of the fibers under test, it’s possible to get a graphical representation of the entire fiber optic link.

Fiberstore2405 OTDR

An OTDR can be used to measure optical distance including locations of the elements like splices, connectors, splitters, multiplexers and faults, as well as end of fiber. Loss and Optical Return Loss (ORL)/Reflectance, such as loss of splices and connectors, ORL of link or section, reflectance of connectors and total fiber attenuation can also be tested by OTDRs.

Not all OTDR are made the same. There are various kinds of OTDR models available, addressing different test and measurement needs. The choosing of an OTDR is based on applications. By thinking of the following questions, you can roughly know what kind of OTDR you need.

  • What kind of networks will you be testing? LAN, metro, long haul?
  • What fiber type will you be testing? Multimode or single-mode?
  • What is the maximum distance you might have to test? 700 m, 25 km, 150 km?
  • What kind of measurements will you perform? Construction(acceptance testing), troubleshooting, in-service?

JDSU MTS-4000 OTDR

Fiberstore offers you 7 factors to help you figure out which OTDR best fits your applications.

  • Size and Weight: important if you have to climb up a cell tower or work inside a building.
  • Display Size: 5″ should be the minimum requirement for a display size; OTDRs with smaller displays cost less but make OTDR trace analysis more difficult.
  • Battery Life: an OTDR should be usable for a day in the field; 8 hours should be the minimum.
  • Trace or Results Storage: 128 MB should be the minimum internal memory with options for external storage such as external USB memory sticks.
  • Bluetooth and/or WiFi Wireless Technology: wireless connectivity enables easily exporting test results to PCs/laptops/tablets.
  • Modularity/Upgradability: a modular/upgradable platform will more easily match the evolution of your test needs; this may be more costly at the time of purchase but is less expensive in the long term.
  • Post-Processing Software Availability: although it is possible to edit and document your fibers from the test instrument, it is much easier and more convenient to analyze and document test results using post-processing software.

Before selecting an OTDR, consider the applications that the instrument will be used for and check the OTDR’s specifications to ensure that they are suited to your applications.

Fiberstore OTDR Solution

Fiberstore OTDRs are available with a variety of fiber types and wavelengths, including single mode fiber, multimode fiber, 1310nm, 1550 nm, 1625 nm, etc. It also supplies OTDRs of famous brands, such as JDSU MTS series, EXFO, YOKOGAWA AQ series and so on. You can find the OTDR best fit your applications in Fiberstore.

FTTH Makes Your Life Better

The way people live, work and play has been changed by the high speed bandwidth carried by fiber optic cables. People communicate via social networks like Facebook or Twitter, share videos online, watch Internet movies on television, take advantages of telemedicine and home based businesses. Without fiber optic cable, none of these activities can be carried out smoothly.

FTTH

To further improve the speed of bandwidth for users, FTTH (fiber to the home) are being widely accepted in cabling. Fiber to the home (FTTH) is the delivery of a communications signal over optical fiber from the operator’s switching equipment all the way to a home or business, thereby replacing existing copper infrastructure such as telephone wires and coaxial cable. By using the FTTH technologies, fiber reaches the boundary of the living space, such as a box on the outside wall of a home.

A key benefit of FTTH is that it provides much faster Internet speeds than twisted pair conductors, DSL or coaxial cable. However, what FTTH can bring for people is not just the faster speed. The real value of FTTH is that it can meet the exploding demand for more services. Therefore, people can do entirely new things and enjoy more new products and services with the networks.

FTTH is widely accepted now and making people’s life much more convenience and better. It also becomes an element like good water, power, transportation to define successful communities. FTTH-powered bandwidth is essential for people who work at home and who want quality life provided by online entertainment, education, culture and e-commerce.

2 Fibers Single-mode FRP Strength member Messenger Wire LSZH FTTH Drop Cable-GJXFH

Fiberstore’s FTTH Optic Fiber Cable Solution

Demand for bandwidth is rising with the introducing of new products and services. As a part of infrastructure, demand for FTTH fiber optic cable is also rising. FTTH Fiber Optic Cable is a kind of special curved optical fiber, which providing greater bandwidth and enhanced network transmission characteristics. This cable replaces the standard copper wire of the local Telco as it can carry high-speed broadband services integrating voice, data and video, and runs directly to the junction box at the home or building.

Fiberstore supplies various FTTH optic fiber cables, like FTTH Indoor Cable, FTTH Drop Cable, FTTH Duct Armored Cable, etc. In order to cut inventory costs and speed up the installation process for our customers, Fiberstore’s FTTH cable designs can simplify your project. For more information please visit Fiberstore’s Online shop (fs.com).

How to Choose the Fittest Network Face Plates?

Although FTTx is now being widely applied, many places are not able to use optical fiber or FTTx. For example, CAT6 or CAT5e cables are still occupying a certain proportion comparing with fiber optic cables. In some places FTTx and CAT5e/CAT6 network cables are being operated at the same time. In the mentioned situations, network face plates should be taken into consideration during cabling.

Network Face Plate is usually a plastic plate with one or more ports, which allows copper network cables to run between rooms beneath floors and behind walls. It is important to choose appropriate network face plates or wall plates during cabling.

Before you install network face plates, you should know which ones satisfy your needs most. The face plates you choose should conform to the standard you have chosen for your overall system. A good choice of network face plates or wall plates will not only help to maintain the quality of your infrastructure, but also save valuable spaces and cost. How to select the appropriate network face plates and wall plates? The following will give you the answer.

First, you should make sure how many types of cables you need to run. Usually, people need multiple medium to maintain communication. For example, telephone, Internet and TV are always the “must-have” medium during home network cabling. They should be connected with different network face plates. You might need several network face plates separately with RJ45 port, RJ11 port and TV port. However, in many situations, those cables come into home from one location. Then, it could be really bothering to install these face plates one by one. In addition, it’s not space saving and the appearance is not nice. Luckily, you can find that many manufacturers are providing network face plates with multiple ports in one to meet your specific networking needs. For example, except the network face plate with one port, Fiberstore also provides many other network face plates like the followings:

  • Face plate with one or more RJ45 port(s) and one or more TV port(s)
  • Face plate with a RJ45 port, RJ11 port and a TV port
  • Face plate with a RJ45 port, a RJ11 port, as well as an electrical socket and switch.

wall face plate with two RJ45 ports and two TV portsone RJ45 port, one RJ11 port, one electrical socket and one switch in a wall face plate

The above picture on the left shows a network face plate with two RJ45 ports and two TV ports. The above picture on the right shows a network face plate with one RJ45 port, one RJ11 port, one electrical socket and one switch.

Fiberstore could even provide RJ45 wall plate with a RJ45 port and a SC port for the situations in which both copper cable and fiber optic cable are being used.

RJ45-SC wall plate

The above picture shows a RJ45 wall jack with a RJ45 port and a SC port.

The size of the network face plate is another thing should be considered during cabling. There are generally 3 types of standard network face plates. They are known as 86 type, 118 type and 120 type network face plates. 86 type network face plate is square, with a size of 86*86mm, with one to three ports. 118 type network face plate is a rectangle network face plate generally with a 118*72mm size or other sizes. 120 type network face plate usually has a size of 120*120mm, 120*60mm or other accordingly.

One more thing cannot be ignored during network cabling is the cable type. The most commonly used copper network cables are CAT5e or CAT6. It is essential to make sure whether the network face plates are suitable for the cables you chose.

By taking the mentioned aspects into consideration, you are sure to find the right network face plates for your needs.

Fiberstore supplies a variety of network face plates, such as AMP Face Plate BS Shuttered, 86 type network face plates, 118 type network face plates. These face plates are available with 1 port, 2 ports, 4 ports, etc. Our high quality network face plates are compliant with international standards with low price and worldwide delivery. They can help you save time & money for your business or project.

Plastic Optical Fiber – A “Consumer” Optical Fiber

If you are thinking of pre-wiring or rewiring your home network, there are many alternatives to consider. POF (Plastic optical fiber) could be one of your options. It is usually called as “consumer” optic fiber, as it is a low-cost optical fiber alternative with flexibility and ease of end finish.

plastic optic fiber

Plastic optic fiber is a large core step-index fiber with a typical diameter of 1 mm, which typically uses PMMA (acrylic), a general-purpose resin as the core material, and fluorinated polymers for the cladding material. It is a specialty fiber has various advantages and is useful for illumination, sensors and low speed short data links and so on.

Plastic optical fiber works in the same manner as glass optical fiber but uses plastic instead of glass. Although POF has a higher attenuation than glass optical fiber, it is acceptable for certain applications. Because it has merits that the glass optical fiber does not have. Unlike glass, plastic optical fiber has a larger core made out of PMMA and larger numerical aperture, which is capable of withstanding tighter bend radius than glass optical fiber. Thus it can be easily be cut and bent to fit in hard-to-reach places. Besides, the cost of plastic optical fiber is much lower.

POF has a data transfer speed lower than glass optical fiber, but comparing with the more traditional copper wiring, POF has a much faster transfer speed. Plastic optical fiber also has the merits that copper wiring does not have. They are as following:

  • POF is Complete immunity to electromagnetic interference (EIM).
  • POF is an electrical insulator, which can be laid down in power ducts.
  • POF has lower weight than copper wiring.
  • POF is cheaper than copper wiring

With the growing demand for high-speed communications over private intranets and the internet, varied applications with plastic optical fiber have been developed and commercialized. Plastic optical fibers can be used as light transmission guide in displays or as sensors and telecommunications cables. The uses of POF can be found in but not limited to the following fields: FTTH, automotive, medical, intelligence, lighting, sensor, digital audio and video interfaces.

If you are looking for plastic optical fiber for cabling, Fiberstore will satisfy your needs. It provides both simplex plastic optical fiber and duplex plastic optical fiber. For more information about Fiberstore’s POF products, you can visit its online store by clicking the following words: plastic optical fiber.

Introduction of Fiber Optic Wall Plate

When talking about fiber optic cabling system, the related products that come to our mind firstly are usually fiber optic cables, fiber optic transceivers, connectors or fiber optic transmission products. However, there are still many other components whose importance should not be ignored. Fiber optic wall plate, or outlet, is one of these components, and is also one of the most visible components in a fiber optic cabling system. This text will introduce you this component and offer you the Fiberstore‘s fiber optic wall plate solution.

Fiber optic wall plate is a flat plastic or metal plate that allows connection to fiber cable carrying optical signals. It serves as a transition point between the fiber optic cable and equipment. Fiber optic wall plates are usually mounted in or on walls, but some of them can also be mounted in floors and ceilings. Fiber optic wall plate includes one or more ports, and each port is available with an adapter.

Applications of Fiber Optic Wall Plate

Fiber optic wall plates are designed to bring fiber to the desk and widely used in multi-floor and high building. It can be found in:

  • FTTH access
  • Telecommunication
  • CATV
  • Data Communication Networks etc.
Types of Fiber Optic Wall Plate

Fiber optic wall plates come in many different types according to their adapter type, port number and faceplate interface.

According to the faceplate interface of the plates, there are bevel fiber optic wall plates and hybrid fiber optic wall plates.

Fiber optic wall plates can contain one or more adapters. The number of ports a plate can have is based on the size of the plate. Here listed some of the fiber optic wall plates:

  • Single port fiber optic wall plates
  • 2-port fiber optic wall plates
  • 3-port fiber optic wall plates
  • 4-port fiber optic wall plates
  • 6-port fiber optic wall plates
  • 8-port fiber optic wall plates
  • 12-port fiber optic wall plates

The following picture shows a single port ST fiber optic wall plate outlet.

wall plate

To satisfy different demands during cabling, sundry kinds of adapters could be installed on fiber optic wall plates. And these adapters could be the same ones or different. If classified by the adapters, the types of fiber optic wall plates will be various. Parts of the fiber optic wall plates classified by the adapters are listed as following:

  • FC fiber optic wall plates outlets
  • SC fiber optic wall plates outlets
  • ST fiber optic wall plates outlets
  • LC fiber optic wall plates outlets
  • SC-ST fiber optic wall plates outlets
  • RJ45-SC fiber optic wall plates outlets
  • SC-ST-LC fiber optic wall plates outlets
  • FC-SC-ST-LC fiber optic wall plates outlets

wall plate pic 2

The above picture shows a 2-port FC bevel fiber optic wall plate outlet. The picture below shows a 4-port SC/ST/FC/LC hybrid fiber optic wall plate outlet.

wall plate pic 3

Fiberstore’s Fiber Optic Wall Plate Solution

Fiberstore supplies different types of fiber optic wall plates, including bevel fiber wall plates with 45° adapter plug-in/out angle and hybrid fiber wall plates/outlets. These wall plates are available with LC, SC, ST, FC adapters (or hybrid with RJ45 port) and up to 4 ports. All the wall plates are with high quality and secure to any surface, drywall, baseboard, and even modular furniture.

Fiber Splice Tray & Wall Mount Network Cabinet–For Better Cabling

Cabling is not some easy thing. Many problems might come out while cabling. Sometimes the fiber optic cable is not long enough. Sometimes there are too many fiber optic cables that need great efforts to ensure the management of them. The protection and maintenance of the fiber optic cable are also essential. These are just some of the most common problems that people meet during cabling. In this article, two common and useful products will be introduced to help you solve the most common problems while cabling. They are fiber splice tray and wall mount network cabinet.

Fiber Splice Tray
Fiber splice tray is a kind of optical distribution frame. Generally, fiber splice tray is a container used to organize and protect fibers and spliced fibers. It is designed to provide space for the connection of fibers and spliced fibers.
Different fiber optic cables can be melted connected directly via the fiber splice tray. In addition, fiber optic cable can be connected with pigtail via the tray, and via the pigtail it can connect out to their fiber optic equipment. With the help of fiber splice trays, the problem that the fiber optic cable is not long enough can be solved. Fiber splice tray is made of engineering plastics and it features as flame retardant, high strength and aging resistance. Thus it can protect the fiber and spliced fibers very well. In addition, as the fiber splice tray provides space to hold the melted connected fibers and spliced fibers, it can help to manage the fiber optic cables to some degree. This function can be seen from the picture of a splice tray below:
OLYMPUS DIGITAL CAMERA
Fiber splice tray is one of the most common components being used during cabling. It can offer various of unique and flexible splice and storage possibilities.

Wall Mount Network Cabinet
Wall mount network cabinet is one of the most commonly used distribution cabinets. It provides a flexible fiber management system for transitioning outside plant cable to inside cable and connector assemblies and can be installed on the wall.
Wall mount network cabinet has great advantages in fiber optic cable management and protection. The wall mount network cabinet is usually layered structure, which helps a lot while organizing equipment and cabling in limited space. Moreover, the maintenance of fiber optic cables connected with wall mount network cabinet is very convenient and efficient. The cabinet generally contains power supply and fan, which can help the fiber optic cables work well and work longer. Various sizes and types of wall mount network cabinets are provided. Factories install different adapters in the cabinet to satisfy the needs of the markets. Costum-made cabinet is also very popular.

wall mount cabinet 2 wall mount cabinet
With the help of wall mount network cabinets, cabling work will be much more easier and systematic. The cabinet provides a safe place for the fiber optic cables connection in limited space. It is now widely used in the cabling of various areas.

The choice of appropriate components during cabling does not only simplify the work, but also helps a lot in cost saving, space savings, products operation and maintenance. Fiberstore Inc. designs, manufactures and sells a comprehensive line of high performance, highly reliable fiber optic communication systems and modules for metropolitan area, local area and storage area networks. Fiberstore can provide different sizes of wall mount network cabinets and various types of fiber splice trays which can contain 4 fibers, 6 fibers, 12 fibers, 16 fibers, 24 fibers, 32 fibers and so on.

LSZH Fiber Optic Cable

When choosing the fiber optic cable for any application, we need to consider the environment where the fiber optic cable will be used. Will the fiber optic cables work well and safely in the environment? What might happen if the cables meet some extreme situations? We must take human safety and environmental protection into consideration when selecting the appropriate cabling solution. Then you can concern the LSZH fiber optic cable in a lot of situations.

LSZH-Distribution-Cable

What is LSZH Fiber Optic Cable?
LSZH fiber optic cable has no difference from other fiber optic cables, but it has a special cable jacket which is made of LSZH materials. LSZH stands for Low Smoke, Zero Halogen. This type of cable jacket has excellent fiber safety characteristics of low smoke, low toxicity and low corrosion. This is because LSZH materials are free of halogenated materials like Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I) and Astatine (At), which are reported to be capable of being transformed into toxic and corrosive matter during combustion and decomposition. LSZH fiber optic cable is now being widely used in many places.

Characteristics of LSZH Fiber Optic Cable
The main characteristics of LSZH fiber optic cables are as following:

  • Release no dangerous smoke and gas during confusion
  • Low emission of toxic gases and halogens during decomposition
  • Low corrosion
  • High flame retardant

The Types of LSZH Fiber Optic Cable
Currently, there are hundreds of different kinds of LSZH fiber optic cables provided for many different uses. The major types of LSZH fiber optic cables now being provided are as following:

  • Single-mode LSZH fiber optic cables
  • Multi-mode LSZH fiber optic cables
  • Double jacket LSZH fiber optic cables
  • Single jacket LSZH fiber optic cables
  • Gel-filled LSZH fiber optic cables
  • Strength membered LSZH fiber optic cables
  • FTTH LSZH fiber optic cables
  • Indoor LSZH fiber optic cables
  • Outdoor LSZH fiber optic cables

Why do We Choose LSZH Fiber Optic Cable?
For the Safety
According to researches, most fire-related deaths are not actually caused by the fire, but by inhalation of large quantities of smoke and toxic gas. Wires and cables might be damaged and burned by the fire and short circuit. Some cables like PVC will release a lot of toxic gas and corrosive matter during the fire. As LSZH material has the characteristics of low smoke, low toxicity, low corrosion and high flame retardant, the choosing of LSZH fiber optic cable in some public space like train, hospital, subway and school is really necessary.
Go for Green
The LSZH fiber optic cable has an environment friendly cable jacket, which satisfies the global need of environment protection. It releases low smoke and low toxic matter during the confusion and decomposition. There is no reason not to use LSZH fiber optic cable when it is appropriate, because the environmental protection is now a pressing problem all over the world.
LSZH fiber optic cable with a good performance in the environmental protection and safety, can be a good choice of many cable installations.

Applications of LSZH Fiber Optic Cable
LSZH fiber optic cable now can be found in many places, especially some public places. Now some places have been asked to use LSZH fiber optic cable in the cabling solution because of its performance. The major uses of LSZH fiber optic cable can be found in the following areas.

  • Hospitals
  • Schools
  • High buildings
  • Airports
  • Libraries
  • Commercial centers
  • Sports centers
  • Mass transit rail systems
  • Nuclear plants
  • Oil refineries and any other applications where the protection of people and equipment from toxic matter and gases is critical.

Now with the development of cables, many areas are using LSZH fiber optic cables. However, the application of LSZH fiber optic cables can still be found in many other areas in the future. It is a kind of fiber optic cable with great prospect.

How to Prevent the Damage caused by Lightning in Fiber Cabling

With the development of the network communications, the optical fiber as a medium used in the integrated cabling systems to transmit data is used by more and more people, because of its advantages such as large transmission rate and distance. It is well known that optical fiber has no electrical conductivity and can prevent from impact current. Fiber optic cables have good protection performance, and the metal components of cable’s insulation value is so high that lightning current can not enter the cable easily. However, because fiber optic cable has strengthened core, especially the direct-buried fiber optic cable has armoring layer, thus when the optical fiber cable line experience lightning, the cables might be destroyed or damaged. And this blog talks about the main measures of lightning protection in fiber cabling.

Lightning Protection for Direct-Buried Fiber Optic Cables

  • Station Grounding Method: the metal part of the cables in the joints should be all connected to make sure the strengthened cores, moistureproof layers, and armoured layers are in connected state in the relay cable lines.
  • Electrical Disconnect Treatment should be done in the cable tapping of moistureproof layers, armoured layers and strengthened cores, and do not connect the ground for the insulation status. This method can avoid the accumulation of induced lightning current in the cables. Also, it can avoid lightning current enetr in the cables by grounding devices, which is caused by the difference of loop impedance to ground between the lightning discharge flow and the cables’ metal components.

Lightning Protection for Aerial Fiber Optic Cables

Aerial fiber optic cables should be electrical connected and connected to the ground every 2 km. The grounding can be directly done or or by suitable surge protection devices.

Typical Lightning Protection for Fiber Optic Cables

After fiber optic cables enter the fiber optic terminal boxes, the boxes should be connect to the ground so they can rapidly release the lightning current to realize the protection when the lightning current enter the fiber optic cables’ metal layers. When using direct-buried fiber optic cables with armoured layers and strengthened cores, the polyethylene outer sheath can be effectively anticorrosive and prevent from rat bites as well as the lightning stroke.

Article Source: http://www.fiberopticshare.com/how-to-prevent-the-damage-caused-by-lightning-in-fiber-cabling.html

Fiber Optic Connector: An Important Part of Fiber Optic Termination

Fiber optics are used for a variety of applications in the photonics industry. Fiber optics are typically connectorized for convenience of mating and coupling. These connectors come in many configurations and styles. A fiber optic connector that was lower loss, lower cost, easier to terminate or solved some other perceived problem is urgently needed to the industry. As a result, about 100 fiber optic connectors have been introduced to the marketplace, but only a few represent the majority of the market. Today, Fiberstore’s Blog are going to show you these commonly used fiber optic connectors.

fiber optic connector

Fiber Optic Connector Types
Commonly used fiber optic connector types include SC, FC, LC, ST, MU, E2000, MTRJ, SMA , DIN as well as MTP & MPO etc. They are widely used in the termination of fiber optic cables, such as fiber optic pigtail, fiber optic patch cables and so on.

LC connector LC Connector (Lucent Connector) — Ferrule diameter = 1.25mm. LC connectors are licensed by Lucent and incorporate a push-and-latch design providing pull-proof stability in system rack mounts. LC connectors are available in single mode and multimode. Externally LC connectors resemble a standard RJ45 telephone jack. Internally they resemble a miniature version of the SC connector. This type of connectors are commonly used in connecting SFP Transceiver Module in Router/Switch. For example, the optic interfaces of Cisco’s SFP transceivers are all LC connectors.
SC connector SC Connector (Subscriber Connector) — Ferrule diameter = 2.5mm. The SC connector is becoming increasingly popular in single-mode fiber optic telecom and analog CATV, field deployed links. But the most commonly used field is to connect GBIC (100Base-FX) in router/switch. The high-precision, ceramic ferrule construction is optimal for aligning single-mode optical fibers. The connectors’ outer square profile combined with its push-pull coupling mechanism, allow for greater connector packaging density in instruments and patch panels. The keyed outer body prevents rotational sensitivity and fiber endface damage. Multimode versions of this connector are also available. The typical insertion loss of the SC connector is around 0.3 dB.
ST connector ST Connector (Straight Tip) — Ferrule diameter = 2.5mm. ST connector’s high-precision, ceramic ferrule allows its use with both multimode and single-mode fibers. The bayonet style, keyed coupling mechanism featuring push and turn locking of the connector, prevents over tightening and damaging of the fiber end. The insertion loss of the ST connector is less than 0.5 dB, with typical values of 0.3 dB being routinely achieved. ST connector is used extensively both in the field and in indoor fiber optic LAN applications, eg. ODF (optical distribution frame). In addition, ST connector is also used to connect GBIC transceiver, usually for 100Base-F.
FC connector FC Connector (Ferrule Connector) — Ferrule diameter = 2.5mm. The FC has become the connector of choice for single-mode fibers and is mainly used in fiber-optic instruments, SM fiber optic components, and in highspeed fiber optic communication links. This high-precision, ceramic ferrule connector is equipped with an anti-rotation key, reducing fiber endface damage and rotational alignment sensitivity of the fiber. The key is also used for repeatable alignment of fibers in the optimal, minimal-loss position. Multimode versions of this connector are also available. The typical insertion loss of the FC connector is around 0.3 dB.
MU connector MU Connector (Miniature Unit) — Ferrule diameter = 1.25mm. MU is a small form factor SC. It has the same push/pull style, but can fit 2 channels in the same Footprint of a single SC. MU was developed by NTT. It is a popular connector type in Japan. Applications include high-speed data communications, voice networks, telecommunications, and dense wavelength division multiplexing (DWDM). MU connectors are also used in multiple optical connections and as a self-retentive mechanism in backplane applications.
MTRJ connector MTRJ Connector (Mechanical Transfer Registered Jack) — Ferrule diameter = 2.45×4.4 mm. MT-RJ is a duplex connector with both fibers in a single polymer ferrule. It uses pins for alignment and has male and female versions. Multimode only, field terminated only by prepolished/splice method.
E2000 connector E2000 Connector — Ferrule diameter = 2.5mm. E2000 connector is a plastic push-pull connector developed by Diamond. The E2000 was developed as an improvement on the SC connector design by having: a latch that retains the connector, a dust cap always in place, and a smaller size. The built in dust cap always stays on the connector protecting the ferrule and blocking harmful laser light when the connector is disconnected. E2000 is available for Singlemode and Multimode applications.
sma SMA Connector (Sub Miniature A) — Ferrule diameter = 3.14mm. Due to its stainless steel structure and lowprecision threaded fiber locking mechanism, this connector is used mainly in applications requiring the coupling of high-power laser beams into large-core multimode fibers. Typical applications include laser beam delivery systems in medical, bio-medical, and industrial applications. The typical insertion loss of an SMA connector is greater than 1 dB.
DIN connector DIN Connector — Ferrule diameter = 2.5mm. DIN connector is a metal screw on connector which is developed by Siemens. Deutsch Telecom mainly uses it. This is a good connector to use where the ruggedness of a metal screw on connector is required but
where there is not enough space for a FC Connector.
mtp&mpo connector MTP and MPO Connector — MTP and MPO are compatible ribbon fiber connectors based on MT ferrule which allow quick and reliable connections for up to 12 fibers. They are intended for installations that require many fiber connections. Up to 12 fibers in a ribbon are stripped to 125um cladding and inserted into 250um spaced parallel grooves. The ferrule also includes two 0.7mm diameter holes, running parallel to the fibers on the outer side of the ferrule. These two holes hold precision metal guide pins which align the fibers with tight tolerances. MTP and MPO connectors feature male and female connector design. Male connectors have two guide pins and female connectors do not. Both connector types need an adapter to mate a pair of male and female connectors. Because MTP and MPO connectors are trying to align so many fibers at once, their coupling loss are typically bigger than single fiber connectors.

 

History of Different Connector Types
The ST connector is the oldest design of the connectors still in common use. It was the first connector to use a 2.5mm ferrule. The FC and DIN connectors improved on the ST connector by: isolating cable tension from the ferrule, keying the location of the ferrule for angle polishing, and threading onto the adapter for a more positive connection. The SC connector was then developed to eliminate having to screw and unscrew the connector every time and to reduce the cost by molding instead of machining the connector. A big advantage of this push/pull connector over a FC connector is that less room is required between connectors on patch panels. The E-2000 was developed as an improvement on the SC connector design by having: a latch that retains the connector, a dust cap always in place, and a smaller size. As patch panel densities increased the LC and MU connectors were developed to reduce the space required for connectors on patch panels. Both of these connectors use a 1.25mm ferrule. The MT-RJ connector was then developed to put transmit and receive fibers into one connector. This was the first connector to use the MT ferrule design as opposed to a 2.5mm or 1.25mm diameter ferrule. The MTP connector was then developed to increase fiber density even more. The MTP currently has 12 fibers in its MT ferrule however a 24-fiber version is under development.

There are many more influences that lead to the development of these different commonly used connector types. This is why all of the different connector types exist. In fact, there are not only these connector types. A multitude of specialty connectors are launched to the market for different application.

Connector Endface Preparation
Once the optical fiber is terminated with a particular connector, the connector endface preparation will determine what the connector return loss, also known as back reflection, will be. The back reflection is the ratio between the light propagating through the connector in the forward direction and the light reflected back into the light source by the connector surface. Minimizing back reflection is of great importance in high-speed and analog fiber optic links, utilizing narrow line width sources such as DFB lasers, which are prone to mode hopping and fluctuations in their output.

polishing type

Flat Polish — a flat polish of the connector surface will result in a back reflection of about -16 dB (4%).
PC Polish — the Physical Contact (PC) polish results in a slightly curved connector surface, forcing the fiber ends of mating connector pairs into physical contact with each other. This eliminates the fiber-to-air interface, there by resulting in back reflections of -30 to -40 dB. The PC polish is the most popular connector endface preparation, used in most applications.
UPC/SPC Polish — in the Super PC (SPC) and Ultra PC (UPC) polish, an extended polishing cycle enhances the surface quality of the connector, resulting in back reflections of -40 to -55 dB and < -55dB, respectively. These polish types are used in high-speed, digital fiber optic transmission systems.
APC Polish — the Angled PC (APC) polish, adds an 8 degree angle to the connector endface. Back reflections of <-60 dB can routinely be accomplished with this polish.

Article Source: http://www.fs.com/blog/fiber-optic-connector-an-important-part-of-fiber-optic-termination.html

Cost-effective Capacity Growth and Investment Protection — Hybrid DWDM/CWDM

Introduction of Hybrid DWDM-CWDM

CWDM is an excellent, cost-effective, first step solution for scaling metro networks. Low cost hybrid DWDM-CWDM modules can support up to 8 channels at 2.5 Gbps. This is sufficient for many networks in the metro space. If capacity needs grow beyond 8 channels, these modules can be used to merge DWDM and CWDM traffic seamlessly at the optical layer. This allows carriers to add many channels to networks originally designed for the more limited CWDM capacity and reach.

Hybrid DWDM-CWDM technology delivers true pay-as- you-grow capacity growth and investment protection. It offers a simple, plug-and-play option for creating hybrid systems of DWDM channels interleaved with existing CWDM channel plans.

 

Advantages of Hybrid DWDM-CWDM

The major advantages of hybrid DWDM-CWDM for carriers are as following:

  • Reduced Cost: CWDM has a significant cost advantage over DWDM due to the lower cost of lasers and the filters used in CWDM modules (CWDM MUX, CWDM OADM etc.). Coarse channel spacing allows more tolerance for channel deviations or wavelength deviations. Therefore, CWDM filters and transmitters are easier, and cheaper, to manufacture. This cost saving becomes quite significant for large deployments.
  • Pay-As-You-Grow: Adding new channels one at a time allows for on-demand service introduction with minimal initial investment, a critical feature in times of reduced OPEX and CAPEX spending.
  • Investment Protection: Although 8 channels may be enough in an initial deployment, it’s important to have an upgrade path to avoid a forklift upgrade to DWDM when growth in demand finally requires significant new capacity. Given the DWDM over CWDM upgrade capability, carriers no longer have to choose between CWDM and DWDM—both options can be deployed simultaneously or as part of a planned future, or incremental, upgrade. Hybrid DWDM-CWDM modules can be used in either the DWDM systems or in the CWDM systems. Current capital investment can always be used in the upgraded network.

Theory of DWDM/CWDM Hybridization

The CWDM frequency grid consists of 16 channels spaced at 20 nm intervals. The eight most commonly used channels are: 1470 nm, 1490 nm, 1510 nm, 1530 nm, 1550 nm 1570 nm, 1590 nm and 1610 nm. Within the pass band of these channels there exists the capacity to add twenty-five 100 GHz spaced DWDM channels under the 1530 nm envelope and twenty-five more under the 1550 nm envelope if the filter is properly designed. The theoretical availability of DWDM channels in the 1530 nm and 1550 nm pass-band is shown in the table below.

Theoretical DWDM Channels in the 1530 and 1550 nm CWDM Pass-Band

 

Practical Application of DWDM/CWDM Hybridization

In practice, adding another 25 DWDM channels in the pass-band of both the 1530 nm and 1550 nm CWDM channels is not achievable because the optical filters are not perfect square functions. The actual filter profile affects the number of channels which can be accommodated. However, actual DWDM filter technology does allow 38 additional channels to clear the CWDM archway as shown in the table below.

Actual DWDM Channels in the 1530 and 1550 nm CWDM Pass-Band

The system impact to adding these channels is equivalent to adding the component in line with existing CWDM equipment. The insertion losses add linearly. Here is a figure that shows the infrastructure in a fully populated CWDM system.

Infrastructure of Hybrid DWDM CWDM System

To add more channels to MUX side of this network, one would plug in a DWDM MUX with the appropriate channels to fall under the pass-band of the existing CWDM filters. The figure below shows the infrastructure of a CWDM system upgraded with 38 additional 100 GHz spaced DWDM channels.

44-Channel Hybrid DWDM-CWDM System

The number of channels present in this hybrid system is 38 DWDM channels plus the existing 6 CWDM channels for a total of 44. The equipment required to go from the first architecture to the second are 2 DWDM multiplexers and demultiplexers, as well as the additional transmitter and receiver pairs required. The additional loss incurred by the upgrade is equal to the additional loss of the DWDM elements and the additional connection points.

Several network types could take advantage of the hybrid architecture. For example, one could increase the capacity of an existing ring by deploying all of the elements above at each node. Or, one could allow DWDM traffic to overlay an existing CWDM network at a pre-determined crossover point.

The two networks would be configured in such a way to allow the DWDM traffic to travel across the CWDM ring. All of the nodes where the DWDM traffic would travel on the CWDM ring would require the DWDM multiplexer and demultiplexer pairs (shown as below).

Hybrid CWDM-DWDM Rings

Another application for the DWDM channels is for long reach links in CWDM rings. If a certain span exists in a CWDM network with a large distance between regenerators, e.g. 100 km, DWDM channels can be used in place of CWDM ones to overcome this distance. The figure below shows a hybrid DWDM-CWDM mixed node.

CWDM-DWDM Mixed Node

System Impact

The added components on the CWDM ring will decrease the link budget for each span by the amount of insertion loss for each new component. The use of high isolation optical filters for the DWDM channels will ensure that cross talk is minimized between closely spaced channels. In the case of very high channel counts, non-linear effects should be taken into consideration. These include self phase modulation and Four-Wave Mixing (FWM).

The lasers used in DWDM networks have a much narrower line width than lasers used in CWDM. As a result the DWDM signals will typically have farther reach, and will undergo less pulse broadening due to chromatic dispersion. However they also lie within the operating range of Erbium-Doped Fiber Amplifier (EDFA). This means that DWDM signals can go un-regenerated for large distances. This limit is reached at the transmitter’s dispersion limit.

Receiver technology is independent of the optical signal present. The same receiver can be used to resolve a CWDM signal as well as a DWDM signal. The InGaAs material used to convert the optical signal into an electrical one has an operating range that includes both wavelength schemes. In the case of a 3R receiver, the receiver should be chosen such that it is compatible with the transmitter’s data rate.

Article Source: http://www.fs.com/blog/cost-effective-capacity-growth-and-investment-protection-hybrid-dwdmcwdm.html

Dual Stage EDFA with DCM Mid-Stage Access – DCM-optimized EDFA

Besides optical amplifiers, modern optical networks also require other components to be place along the link, such as the Dispersion Compensation Module (DCM) used to correct signal distortion due to Chromatic Dispersion of the transmission fiber. Since the attenuation of DCM can be quite large, in the range of 5 to 10 dB, additional amplification is needed to accommodate them. In order to minimize the Optical Signal Noise Ratio OSNR and cost impact of this addition amplification, it is beneficial to place the DCM between two amplifiers.

A dual stage EDFA amplifier is basically two amplifiers in one package, where there is access for an optical component such as a DCM to be placed between them. In this configuration, it is called a DCM-optimized EDFA. Most often the first amplifier (pre-amplifier) is variable gain, and the second (booster amplifier) is fixed gain, such that the amplifier as a whole provides variable gain operation. The control of both amplifiers is combined, in other words the user sets the required net gain of the entire combination (including the DCM), and the control units sets the gain of each of the two amplifier in order to achieve the net gain.

Note: DCM-optimized EDFA is named because of using DCM as the mid-stage access. The DCM EDFA can be generally provided as a stand-alone module or in a managed 1RU package with the DCM integrated within. Fiberstore’s Dual Stage DCM-optimized EDFA is a stand-alone module without the DCM which need to be bought separately. In this way, customers could choose the right dispersion compensation modules to meet their own requirements.

DCM-optimized EDFA

Dispersion Compensation Module (DCM)

Here is the basic scheme for a dual stage EDFA amplifier with DCM mid-stage access. The two amplifiers are packaged in the same module and are controlled together with the mid-stage device (i.e. the DCM) as a single unit. Additionally, each amplifier also has its own local control loops.

Dual Stage EDFA with DCM Mid-Stage Access

The amplifiers are designed apriori to take into account the DCF loss. For example, the dynamic range of the input detectors of both amplifiers is set accordingly, and the optical performance, such as Noise Figure (NF), is specified already taking the DCM loss into account. Since the DCM is often implemented using special Dispersion Compensation Fiber (DCF), there can be a large optic al delay between the first and the second stage of the amplifier. For this reason transi ent suppression of each amplifier ne eds to be performed separately, and consequently each amplifier has its own pump and own local control mechanism (in addition to the overall control used to set the net gain).

Advanced Optical Components – Optical Attenuator

What is Optical Attenuator?

Optical Attenuator (or fiber optic attenuator) is a passive device that is used to reduce the power level of an optical signal. The attenuator circuit allows a known source of power to be reduced by a predetermined factor, which is usually expressed as decibels (dB). Optical attenuators are generally used in single-mode long-haul applications to prevent optical overload at the receiver.

Principles of Optical Attenuators

Optical attenuators use several different principles in order to accomplish the desired power reduction. Attenuators may use the Gap-Loss, Absorptive, or Reflective technique to achieve the desired signal loss. The types of attenuators generally used are fixed, stepwise variable, and continuously variable.

Gap-Loss Principle

The principle of gap-loss is used in optical attenuators to reduce the optical power level by inserting the device in the fiber path using an in-line configuration. Gap-loss attenuators are used to prevent the saturation of the receiver and are placed close to the transmitter. They use a longitudinal gap between two optical fibers so that the optical signal passed from one optical fiber to another is attenuated. This principle allows the light from the transmitting optical fiber to spread out as it leaves the optical fiber. When the light gets to the receiving optical fiber, some of the light will be lost in the cladding because of gap and the spreading that has occurred. The gap-loss principle is shown in the figure below.

Gap-Loss Principle

The gap-loss attenuator will only induce an accurate reduction of power when placed directly after the transmitter. These attenuators are very sensitive to modal distribution ahead of the transmitter, which is another reason for keeping the device close to the transmitter to keep the loss at the desired level. The farther away the gap-loss attenuator is placed from the transmitter, the less effective the attenuator is, and the desired loss will not be obtained. To attenuate a signal farther down the fiber path, an optical attenuator using absorptive or reflective techniques should be used.

Note: The air gap will produce a Fresnel reflection, which could cause a problem for the transmitter.

Absorptive Principle

The absorptive principle, or absorption, accounts for a percentage of power loss in optical fiber. This loss is realized because of imperfections in the optical fiber that absorb optical energy and convert it to heat. This principle can be employed in the design of an optical attenuator to insert a known reduction of power.

The absorptive principle uses the material in the optical path to absorb optical energy. The principle is simple, but can be an effective way to reduce the power being transmitted and/or received. Here is the principle of the absorption of light.

Absorptive Principle

Reflective Principle

The reflective principle, or scattering, accounts for the majority of power loss in optical fiber and again is due to imperfections in the optical fiber, which in this case cause the signal to scatter. The scattered light causes interference in the optical fiber, thereby reducing the amount of transmitted and/or received light. This principle can be employed in the planned attenuation of a signal. The material used in the attenuator is manufactured to reflect a known quantity of the signal, thus allowing only the desired portion of the signal to be propagated. This reflective principle is shown in the figure below.

Reflective Principle

Types of Optical Attenuators

>>According to the principles behind the attenuator theories, there are three types of optical attenuators: Fixed Attenuator, Stepwise Variable Attenuator, and Continuously Variable Attenuator.

Fixed Attenuator

Fixed Attenuators are designed to have an unchanging level of attenuation. They can theoretically be designed to provide any amount of attenuation that is desired. The output signal is attenuated relative to the input signal. Fixed attenuators are typically used for single-mode applications.

Stepwise Variable Attenuator

A stepwise variable attenuator is a device that changes the attenuation of the signal in known steps such as 0.1 dB, 0.5 dB, or 1 dB. These attenuators may be used in applications dealing with multiple optical power sources. For example, if there are three inputs available, there may be a need to attenuate the signal at a different level for each of the inputs. Conversely, they may also be used in situations where the input signal is steady, yet the output requirements change depending on the device that the signal is output to. Note: The stepwise variable attenuators should be used in applications where the inputs, outputs, and operational configurations are known.

Continuously Variable Attenuator

A continuously variable attenuator is an optical attenuator that can be changed on demand. It generally has a device in place that allows the attenuation of the signal to change as required. Continuously variable attenuators are used in uncontrolled environments where the input characteristics and/or output need continually change. This allows the operator to adjust the attenuators to accommodate the changes required quickly and precisely without any interruption to the circuit.

Note: Both the stepwise variable attenuator and continuously variable attenuator are collectively known as Variable Optical Attenuator (VOA). When people talk about the VOA attenuator, it generally means a continuously variable optical attenuator.

>>According to the different connector types, there are several types of optical attenuators: LC attenuator, SC attenuator, ST attenuator, FC attenuator, E2000 attenuator etc., available in UPC/APC polish types.

Packaging of Optical Attenuators

Optical attenuators typically come in two forms of packaging: bulkhead attenuator and in-line attenuator. The bulkhead optical attenuators can be plugged into the receiver receptacle. The in-line optical attenuators resemble a fiber patch cord and is typically used between the patch panel and the receiver. Here are a 10 dB Fixed LC/UPC Bulkhead Optical Attenuator and a 0~60 dB LC/UPC to LC/UPC In-Line Variable Optical Attenuator from Fiberstore.

10 dB Fixed LC/UPC Bulkhead Optical Attenuator 0~60 dB LC/UPC to LC/UPC In-Line Variable Optical Attenuator

What Technology Should be Valued at the Next Generation Data Center Network

With the continual?expansion of business data center, the most several difficult problems for them are mainly about divided network environments, simple says, separate data network, separate storage network, separate calculation?network, protocols and there are different disadvantages of standards. Different networks need different cards, space, power and cooling infrastructures for their business. Interspersed interlaced network cabling may make many administrators feel dizzy. Aimed at different network environments, the company needs a professional technical team to support, manage, maintenance, these problems all block the forward developments of data center, let alone meet the future of cloud computing.?The figure shows?modern data center.

Modern data center

You may ask, what qualities we are taken for the next generation data center networks? Now we can see the characteristics, such as simplicity, virtualization features, can accommodate the expansion of the size of the data center, support higher bandwidth, low latency, non-blocking and so on. But as for these features, mainstream network equipment vendors aimed the advantages of their products and solutions to this goal, so if there is an architecture able to support these features do? The answer is yes, unified architecture (Unified Fabric), regardless of Cisco UCS. Brocade VCS, juniper3-2-1 plan, H3C’s unified fabric, also exist Unified Fabric. This page we just say two points.

The key technology under Unified Architecture (Unified Fabric)

Gigabit Ethernet

With the reduction of gigabyte networks at the server connections, Gigabit Ethernet share is rising, which maily due to the growth in the enterprise data center network traffic.In fact, with the 40G / 100G standard developments, it is sure that Gigabit Ethernet replacing the gigabyte networks, the birth of the Gigabit sfp+ transceiver?standard which has low power, sfp+ direct attach cable?can be achieved in the case of low-cost Gigabit Ethernet. And just mainstream might not be enough, the following what I will be introduced to toward greater success.

FCoE protocol (Fiber Channel over Ethernet)

FCoE is one of the most shining technology data center network currently, any vendors have to talk about the technology of the developments of their products. FCoE refers to the Fiber Channel over Ethernet, it can insert fiber channel information into the Ethernet packet, so that the Fiber Channel storage devices -SAN server requests and data can be transmitted over an Ethernet connection, without the need for a dedicated Fiber Channel fabric . Its main benefits: First, make storage traffic and network traffic share the same Ethernet cable and a fusion of the card, simplifying management and reducing energy consumption. Second, provide the same performance with optics. The third is the ability to integrate effectively existing SAN.

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