A Brief Overview of Fiber Optic Cable

Introduction

A fiber optic cable, also known as optical fiber cable, is a network cable that contains two or more glass or plastic fiber cores located within a protective coating and covered with a plastic PVC outer sleeve. It’s correlated with transmission of information as light pulses along a glass or plastic strand or fiber. It’s designed for long distance, very high performance data networking and telecommunications. It has many advantages in optical fiber communication, such as large capacity, long relay distance, good security, free from electromagnetic interference and copper saving.

fiber- optic- cable

Types of Fiber Optic Cables

According to the transmission mode of light in optical fiber, fiber optic cable can be divided into single-mode fiber (SMF) and multimode fiber (MMF). Although they all belong to optical cables and aim at transmitting information, they still have some slight differences.

SMF & MMF

Single-Mode Fiber

Literally, Single-mode fiber is a single stand of glass fiber with a diameter of 8.3 to 10 microns that has one mode of transmission. Due to its smaller diameter, single-mode fiber is used for long-distance signal transmission, which minimizes the reduction in signal strength. Single-mode fiber also has a considerably higher bandwidth than multimode fiber. The light source used for single-mode fiber is typically a laser, which makes it more expensive than multimode fiber.

Multimode Fiber

By comparison, multimode fiber cable, with a diameter of about 62.5 microns, allows multiple mode of light to propagate through it simultaneously, thus forming mode dispersion. Mode dispersion technology limits the bandwidth and distance of multimode fiber. Therefore, multimode fiber features larger core diameter and short transmission distance. Multimode fiber typically uses an LED to create the light pulse, which makes it cheaper than single-mode fiber.

Both single-mode and multimode fiber can handle 10G speeds. The most evident difference between them lies in the distance. Within a data center, it’s typical to use multimode fiber which can get you 300-400 meters. If you have very long runs or are connecting over longer distance, single-mode fiber can get you 10 km, 40 km, 80 km, or even farther. You just need to use the appropriate optic for the distance required.

Fiber Cable Uses

It’s widely acknowledged that optical cables are usually applied into computer networking and telecommunication due to its ability to transmit data and information. What’s more, it’s also used by military and space industries as means of communication and signal transfer, in addition to its ability to provide temperature sensing. In recent years, fiber cable is frequently used in a variety of medical instruments to provide precise illumination. An endoscope, for example, is a flexible tube containing several optical cables. When it slips into the patient’s mouth, nose, digestive tract, and other heart areas that are not visible outside the body, the doctor can see the changes through the endoscope. Other medical applications for fiber optics include X-ray imaging, biomedical sensors, light therapy and surgical microscopy.

Conclusion

From the aforementioned article, we can see that fiber optic cables have different types with different features, and are widely used in telecommunication, military, medical applications, etc. If you would like to know more or would like assistance in choosing the appropriate optical fiber cable, welcome to visit our website www.fs.com for more detailed information. FS will provide more choices and better services for our clients.

Introduction to Fiber Optic Pigtails

During the process of fiber optic cable installation, cable connection is important to ensure the low attenuation and low return loss of signal transmission between cable and equipment. And fiber optic pigtail is a commonly used component for the connection of optical network. It is a piece of cable terminated with fiber optic connectors at one end and no connector at the other end. In this way, the connector side can be linked to the equipment and the other side can be fused with optical cable fibers. This article will emphasize on the types of fiber optic pigtails and their applications.

Here are two classifications of fiber optic pigtails. Firstly classified by connectors, fiber optic pigtails has seven types including E2000, LC, SC, ST, FC, MU and MTRJ. Secondly classified by fibers, fiber optic pigtails has two types as single-mode and multimode.

Classification of Connector

LC-fiber-optic-pigtail

1)LC fiber optic pigtail uses the LC connector developed by Lucent Company. LC connector is now one of the most popular connectors in the world. A 1.25mm ceramic ferrule makes LC fiber optic pigtail a better choice for low cost but high precision signal transmission.

SC-fiber-optic-pigtail

2) SC fiber optic pigtail uses the SC connector developed by Nippon Telegraph and Telephone. SC connector has a ceramic ferrule of 2.5 mm. Its light weight and cost-effective features enable different applications of SC fiber optic pigtail.

 

ST-fiber-optic-pigtail

3)ST fiber optic pigtail uses the ST connector developed by American Telephone & Telegraph. ST connector has a 2.5mm bayonet-styled ferrule. It is one of the eldest generations of fiber optic connectors. But it is still used for many fiber optic applications, especially for multimode fiber optic communications.

FC-fiber-optic-pigtail

4)FC fiber optic pigtail uses the FC connector developed by Nippon Electric Company. The connector features the screw type structure and high precision ceramic ferrule. FC fiber optic pigtail is usually used for general fiber optic applications.

 

Classification of Fiber Types

Single-mode fiber and multimode fiber are both used for fiber optic pigtails. The single-mode fiber optic pigtail has a 9/125 micron core size. SC, LC, ST, FC and E2000 connectors are all fit for this kind of fiber. As for multimode fiber optic pigtails, there are two different core sizes. One is 62.5/125 micron of OM1, and the other is 50/125 micron of OM2, OM3, OM4. SC, LC, ST, FC connectors are adaptable to multimode fiber optic pigtails.

Applications

Fiber optic pigtail sometimes has multiple fiber strands, including 4 fibers, 6 fibers, 8 fibers, 12 fibers, 24 fibers, 48 fibers and so on. This helps the effective interconnection and cross-connect in various applications. Since fiber optic pigtail supports fusion splicing, it is often used with devices like optical distribution frames, splice closures and cross cabinets.

Conclusion

In summary, fiber optic pigtail is a cable that only one end is terminated with connectors. The other end can be melted with optical fiber for a permanent connection. You may choose the adaptable fiber optic pigtail from the perspective of connector types, fiber types, strand numbers, etc. Hope this article can provide a little help.

Overview of Single-mode Fiber Types

According to the light transmission mode, optic fibers can be classified into single-mode and multimode. It’s easy to categorize multimode fiber into four types of OM1, OM2, OM3 and OM4. However, when it comes to single-mode, it may not be as simple as you think. The classification of single-mode fiber is much more complicated than multimode fiber. ITU-T G.65x series and IEC 60793-2-50 (published as BS EN 60793-2-50) are two primary sources for single-mode fiber specification. This article will mainly focus on the ITU-T G.65x series.

The following table introduces 19 ITU-T specifications of single-mode fiber:

Name Type
ITU-T G.652 ITU-T G.652.A, ITU-T G.652.B, ITU-T G.652.C, ITU-T G.652.D
ITU-T G.653 ITU-T G.653.A, ITU-T G.653.B
ITU-T G.654 ITU-T G.654.A, ITU-T G.654.B, ITU-T G.654.C
ITU-T G.655 TU-T G.655.A, ITU-T G.655.B, ITU-T G.655.C, ITU-T G.655.D, ITU-T G.655.E
ITU-T G.656 ITU-T G.656
ITU-T G.657 ITU-T G.657.A, ITU-T G.657.B, ITU-T G.657.C, ITU-T G.657.D

Each type has its own area of application and the evolution of these optical fiber specifications reflects the evolution of transmission system technology from the earliest installation of single-mode optical fiber to the present day. Choosing the right one for your project can be vital in terms of performance, cost, reliability and safety. Now, let’s have a look at the differences of G.65x series specifications for single-mode fiber respectively.

G.652

The ITU-T G.652 fiber is known as standard SMF (single-mode fiber) and is the most commonly deployed fiber. It comes in four variants (A, B, C, D). A and B have a water peak. C and D eliminate the water peak for full spectrum operation. The G.652.A and G.652.B fibers are designed to have a zero-dispersion wavelength near 1310 nm, therefore they are optimized for operation in the 1310nm band. They can also operate in the 1550nm band, but it is not optimized for this region due to the high dispersion. These optical fibers are usually used within LAN, MAN and access network systems. The more recent variants (G.652.C and G.652.D) feature a reduced water peak that allows them to be used in the wavelength region between 1310 nm and 1550 nm supporting Coarse Wavelength Division Multiplexed (CWDM) transmission.

G.652

G.653

G.653 fiber was developed to address this conflict between best bandwidth at one wavelength and lowest loss at another. It uses a more complex structure in the core region and a very small core area, and the wavelength of zero chromatic dispersion was shifted up to 1550 nm to coincide with the lowest losses in the fiber. Therefore, G.653 fiber is also called dispersion-shifted fiber (DSF). G.653 has a reduced core size, which is optimized for long-haul single-mode transmission systems using erbium-doped fiber amplifiers (EDFA). However, its high power concentration in the fiber core may generate nonlinear effects. One of the most troublesome, four-wave mixing (FWM), occurs in a Dense Wavelength Division Multiplexed (CWDM) system with zero chromatic dispersion, causing unacceptable crosstalk and interference between channels.

G.653

G.654

The G.654 specifications entitled “characteristics of a cut-off shifted single-mode optical fiber and cable”. It uses a larger core size made from pure silica to achieve the same long-haul performance with low attenuation in the 1550nm band. It usually also has high chromatic dispersion at 1550 nm, but is not designed to operate at 1310 nm at all. G.654 fiber can handle higher power levels between 1500 nm and 1600 nm, which is mainly designed for extended long-haul undersea applications.

G.655

G.655 is known as non-zero dispersion-shifted fiber (NZDSF). It has a small, controlled amount of chromatic dispersion in the C-band (1530-1560 nm), where amplifiers work best, and has a larger core area than G.653 fiber. NZDSF fiber overcomes problems associated with four-wave mixing and other nonlinear effects by moving the zero-dispersion wavelength outside the 1550nm operating window. There are two types of NZDSF, known as (-D)NZDSF and (+D)NZDSF. They have respectively a negative and positive slope versus wavelength. Following picture depicts the dispersion properties of the four main single-mode fiber types. The typical chromatic dispersion of a G.652 compliant fiber is 17ps/nm/km. G.655 fibers were mainly used to support long-haul systems that use DWDM transmission.

G.655

G.656

As well as fibers that work well across a range of wavelengths, some are designed to work best at specific wavelengths. This is the G.656, which is also called Medium Dispersion Fiber (MDF). It is designed for local access and long haul fiber that performs well at 1460 nm and 1625 nm. This kind of fiber was developed to support long-haul systems that use CWDM and DWDM transmission over the specified wavelength range. And at the same time, it allows the easier deployment of CWDM in metropolitan areas, and increases the capacity of fiber in DWDM systems.

G.657

G.657 optical fibers are intended to be compatible with the G.652 optical fibers but have differing bend sensitivity performance. It is designed to allow fibers to bend, without affecting performance. This is achieved through an optical trench that reflects stray light back into the core, rather than it being lost in the cladding, enabling greater bending of the fiber. As we all know, in cable TV and FTTH industries, it is hard to control bend radius in the field. G.657 is the latest standard for FTTH applications, and, along with G.652 is the most commonly used in last drop fiber networks.

Conclusion

There are different types of single-mode fiber used for different application. G.657 and G.652 are typically favored by planners and installers, and G.657 is particularly deployed for FTTH applications because of a larger bend radius. And G.655 has been taken the place of G.643 used for WDM system. In addition, G.654 is usually applied to the subsea area. To know more information about single-mode fiber, you are welcome to visit the website at FS.COM.

What Should You Know Before Choosing the Single-mode Fiber?

Fiber optical cable has single-mode and multimode type. Multimode fiber includes types of OM1, OM2, OM3, 0M4. How many kinds of single-mode fiber? There are two primary specifications of single-mode fiber. One is the ITU-T G.65x series, and the other is IEC 60793-2-50 (published as BS EN 60793-2-50). This article will introduce ITU-T G.65x series.

single-mode fiber

There are 19 types of single-mode fiber specifications defined by ITU-T (shown in the following table). Different type has different application area. From the change of single-mode fiber specifications, we can see the evolution of transmission system technology. As so many kinds of single-mode fiber, which one should you choose to get perfect performance with the fewest cost? Following will tell about each specifications in details.

ITU-T Specifications Type
ITU-T G.652 ITU-T G.652.A, ITU-T G.652.B, ITU-T G.652.C, ITU-T G.652.D
ITU-T G.653 ITU-T G.653.A, ITU-T G.653.B
ITU-T G.654 ITU-T G.654.A, ITU-T G.654.B, ITU-T G.654.C
ITU-T G.655 ITU-T G.655.A, ITU-T G.655.B, ITU-T G.655.C, ITU-T G.655.D, ITU-T G.655.E
ITU-T G.656 ITU-T G.656
ITU-T G.657 ITU-T G.657.A, ITU-T G.657.B, ITU-T G.657.C, ITU-T G.657.D

ITU-T G.652

ITU-T G.652 fiber is also known as standard SMF (single-mode fiber) and is the most commonly deployed fiber. It comes in four variants (A, B, C, D). A and B have a water peak. C and D eliminate the water peak for full spectrum operation. G.652.A and G.652.B fibers are designed with a zero-dispersion wavelength near 1310 nm, which can be optimized for the operation in 1310nm band. They can also operate in 1550nm band, but it is not optimized for this region due to the high dispersion. The two fibers are usually used within LAN, MAN and access network systems. While G.652.C and G.652.D reduce water peak and can be used in the wavelength region between 1310 nm and 1550 nm supporting Coarse Wavelength Division Multiplexed (CWDM) transmission.

ITU-T G.653

ITU-T G.653 fiber uses a more complex structure in the core region and a very small core area, and the wavelength of zero chromatic dispersion was shifted up to 1550 nm to coincide with the lowest loss in the fiber. It can address this conflict between best bandwidth at one wavelength and lowest loss at another. So G.653 fiber is also called dispersion-shifted fiber (DSF). It has a smaller core size, which is optimized for long-haul transmission system combined with erbium-doped fiber amplifiers (EDFA). However, its high power concentration in the fiber core may generate nonlinear effects. What’s more, four-wave mixing (FWM) occurs in a Dense Wavelength Division Multiplexed (CWDM) system with zero chromatic dispersion, causing unacceptable crosstalk and interference between channels.

ITU-T G.654

G.654 is called “characteristics of a cut-off shifted single-mode optical fiber and cable”. It uses a larger core size made from pure silica to achieve the same long-haul performance with low attenuation in the 1550nm band. It has high chromatic dispersion at 1550 nm but can’t operate at high chromatic dispersion of 1310 nm. G.654 fiber can handle higher power levels between 1500 nm and 1600 nm, which is mainly designed for extended long-haul undersea applications.

ITU-T G.655

G.655 is known as non-zero dispersion-shifted fiber (NZDSF). It has a small, controlled amount of chromatic dispersion in the C-band (1530-1560 nm), where amplifiers work best, and has a larger core area than G.653 fiber. NZDSF fiber can deal with four-wave mixing and other nonlinear effects by moving the zero-dispersion wavelength outside the 1550-nm operating window. There are two types of NZDSF, known as (-D)NZDSF and (+D)NZDSF. Each one has a negative and positive slope versus wavelength. G.655 fibers are mainly used to support long-haul transmission in DWDM system.

ITU-T G.656

G.656 fiber is called Medium Dispersion Fiber (MDF). It’s designed for local access and long haul fiber that performs well at 1460 nm and 1625 nm. This kind for fiber can support long-haul systems that use CWDM and DWDM transmission over the specified wavelength range. And at the same time, it allows the easier deployment of CWDM in metropolitan areas, and increase the capacity of fiber in DWDM systems.

ITU-T G.657
G.657 fiber was originally designed to be compatible with the G.652 fibers but have different bend sensitivity performance. It allows fibers to bend without affecting performance. This is achieved through an optical trench that reflects stray light back into the core and avoids the light lost in the cladding. In reality, it’s hard to control bend radius in the field, such as FTTH applications. G.657 is the latest standard for FTTH applications, and, along with G.652 is the most commonly used in last drop fiber networks.

Conclusion

From the above, different kinds of single-mode fibers have different applications. G.643 is not often used in WDM system because of some problems and is replaced by G.655. G654 is mainly for submarine use. G656 is designed for specific wavelengths. G.657 is compatible with the G.652 but has a larger bend radius than G.652, which is especially suitable for FTTH applications. Now a better understanding of these single-mode fibers will help you to choose the most suitable single-mode fiber.