Fiber Optic Connector Types, Market, & Installation

Over the years, fiber optic connectors are no longer a deep concern for network installers. The industry standards of making connectors replaced the complex installation. A number of fiber optic connector types have been evolved and withstood the test of time to become industry standards. The main types of fiber optic connectors include: ST, FC, SC, and LC. These connectors come in many configurations and usages. This article touches on the very basics of fiber optic connectors types, market as well as its installation.

Fiber optic connector

Fiber Optic Connector Type

The common fiber optic connector types include ST, SC, FC, LC, MU, E2000, MTRJ, SMA, DIN as well as MTP & MPO etc. Each one has its own advantages, disadvantages, and capabilities. All fiber optic connectors have four basic components, which are the ferrule, connector body, cable, and coupling device. They have been widely used in the termination of fiber optic cables, such as fiber optic pigtail, fiber optic patch cables and so on. In this passage, we would mainly give brief introduction to the four most common fiber optic connector types.

—ST Connector (Straight Tip)

One most common of fiber optic connectors is the ST connector. This simplex fiber connector evolved from previous designs and was finally introduced by AT&T in the mid-late 1980s. It has become the de-facto standard in the security market and is commonly used in the AV market on such products as HDSDI, RGB/DVI, and others. It is available in both multimode and singlemode versions. The insertion loss of the ST connector is less than 0.5 dB, with typical values of 0.3 dB being routinely achieved. It is relatively easy to terminate in the field. Besides, it has good strain relief and good, but not exceptional attenuation characteristics.

ST fiber optic connector

—LC Connector (Lucent Connector)

Developed by Lucent Technologies, the LC fiber optic connector has become the ubiquitous fiber optic connector for telecom applications. But LC connector does not stand for Lucent Connector. It is used in conjunction with small form pluggable (SFP) optical transceivers. These SFP devices are now becoming very common in Pro AV applications for such products as HDMI, DVI, audio, optical distribution amplifiers, optical/electrical/optical (OEO) switches, and so forth. The LC connector is smaller than all other connectors and is a push-pull design connector.

LC fiber optic connector

—SC Connector (Subscriber Connector)

The SC fiber optic connectors are common in singlemode fiber optic telecom applications and analog CATV. Like the LC connector, this is also a push-pull design and is also commonly used in patch panels that act as the connector interface between the main field cable and smaller patch cords connected to the fiber transmission equipment. Some manufacturers of fiber AV equipment also use SC connectors in conjunction with their optical emitter and detector devices.

SC fiber optic connector

—FC Connector (Ferrule Connector)

The FC fiber optic connector has become the connector of choice for singlemode fiber. It is mainly used in fiber optic instruments, singlemode fiber optic components, and high-speed 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.

FC fiber optic connector

You can check the detailed specification of the above four fiber optic connectors on the below table.

Connector Type Singlemode (9/125) Insertion Loss (dB) Multimode Insertion Loss (dB Return Loss (dB)
ST Connector ≤0.5 ≤0.5 ≥40
LC Connector ≤0.25 N/A ≥40
SC Connector ≤0.25 ≤0.5 ≥50
FC Connector ≤0.25 ≤0.5 ≥50

Fiber Optic Connector Market

The business of global fiber optic connectors have achieved big success over the past few years. The global fiber optic connector market is expected to reach USD 5.9 billion by 2025, according to a new report by Grand View Research, Inc. and is expected to gain traction over the forecast period. The global marketplace is majorly driven by the growing adoption of the fiber optic technology. The fiber optic connector market type includes different fiber optic connectors such as SC connector, LC connector, FC connector, ST connector, MTP connector, and others. Based on fiber optic applications, the market is segmented into military & aerospace, oil & gas, telecom, medical, BFSI, railway, and others.

Fiber Optic Connector Installation

It is easy to install fiber optic connector, a fiber optic cable connection can be completed within 30 minutes. Just follow the following steps:

  • Step Ⅰ: Strip the plastic jacket at the end of the fiber optic cable. Optic cable ends have jackets to prevent any damage in shipping from the manufacturer. Clamp the plastic jacket, using a fiber optic stripper tool, which has a designated slot to fit the size of a fiber optic jacket. Squeeze the handles of the stripper like pliers. Pull the jacket away from the fiber optic cable.
  • Step Ⅱ:Open the back chamber of the epoxy glue gun by twisting off the back cap. Insert the epoxy glue tube into the chamber and squeeze lightly. You will only need a few ounces of glue for the task. Screw the cap back on the epoxy glue gun chamber.
  • Step Ⅲ:Inject epoxy glue into the fiber optic connector socket. Each fiber optic connector has two sockets on each side of it to form the connection. Insert the glue gun into the connector socket. Press and hold the trigger to insert the glue. The glue should spot should not be larger than an eye pupil.
  • Step Ⅳ:Insert one fiber optic cable end into the connector sockets. Hold the cable in the socket and count to 10. Let go of the fiber optic cable and connector. Check that the cable stays in position once you let go of it.
  • Step Ⅴ:Place the new fiber optic connection into an an epoxy curing oven. Turn on the oven and turn the timer knob to six minutes. Insert the fiber optic connector attached to the cable into one of the curing oven slots. Press the start button on the oven. Pull out the connector from the oven slot. Wiggle the connector end to test the stability of the connection. If it seems fragile, reinsert the connector into the oven and cook it for a few more minutes. Repeat steps three to five to seal the fiber optic connector on both sides.

Conclusion

This article mainly discussed about the fiber optic connector type, fiber optic connector market, as well as its installation. With the wide variety of fiber optic connectors available today, companies can easily convert to fiber optic networks and start enjoying the benefits of a faster, more efficient work environment. If you need fiber optic connectors, FS.COM is a wise choice. They provide a full range of fiber optic connectors and offer customdized service. The fiber optic connect market ahead will be more beoyant, we shall see.

How to Terminate Bare Fiber With Fiber Optic Connector?

There are usually two ways for fiber optic termination. Bare optic fiber can be either spliced with another fiber for a permanent joint or connected with fiber optic connector for a temporary joint. When using the fiber optic connector, we can easily install or uninstall the cable for various applications. This type of termination is more flexible and simple to operate. It is also time-saving to use fiber optic connectors for cable connectivity. However, do you know the right process to terminate bare fiber with fiber optic connector? This article will guide you step by step.

Common Fiber Optic Connectors

Let’s start from the fiber optic connectors. Choosing the right kind of connector for your termination is extremely important. In today’s market, four types of fiber optic connectors are widely used for terminating single fibers. They are LC, SC, ST and FC connectors. LC connector has a 1.25mm ceramic ferrule which is only half the size of other connectors. It’s a snap-in connector usually used for high-density applications. SC connector uses a 2.5mm ceramic ferrule and also features a snap-in connection for quick cable patching. Different from other connectors, ST connector uses a bayonet twist-lock connection with 2.5mm ferrule. Moreover, FC is a screw type connector with 2.5mm ferrule but is becoming less popular than LC and SC connectors.

common-fiber-optic-connector

Connector Polish Styles

When terminating the optic fiber with connector, you should also decide the polish type if the connector is not polished in advance. Generally, connector end face will be polished to minimize back reflection of light. Using the mated polish styles, light can propagate through connectors with lower fiber loss. There are four types of polish styles – flat, PC, UPC and APC polishes. Among them, UPC and APC types are more popular in the industry. The major difference between UPC and APC connectors is that the APC type is polished at an 8-degree angle while UPC has no angle, but they are both slightly curved for better core alignment. As for the color, UPC connector is usually blue and APC connector is green.

upc-apc-polish

Important Precautions

Fiber optic cable is very fragile and sensitive to contamination, thus we need to pay more attention to the precautions before starting termination. Here lists some general precautions as a reference:

  • Always keep dust cap on unused connectors. Store spare dust caps in a dust free environment.
  • Remember to clean the connector and fiber before termination.
  • Make sure there is no laser light in the fiber during termination process.
  • Do not bend the optic fiber at a radius less than 25 mm.
Termination Process

When everything is ready, we can begin the fiber optic termination. The followings are the specific steps.

  • Step 1, measure and mark the cable jacket to the desired length(usually 35 mm). Place jacket stripper on mark and squeeze gently until cutter closes. Pull the cut section off the cable.
  • Step 2, measure and mark kevlar to the desired length(usually remain 7 mm). Use scissors to cut away extra kevlar.
  • Step 3, measure and mark the buffer to the desired length(usually remain 16 mm). Strip the buffer in several small lengths to avoid fiber damage.
  • Step 4, use a lint-free, alcohol-soaked tissue to clean the fiber.
  • Step 5, fill the syringe with adhesive, and slowly inject the adhesive into the ceramic tip.
  • Step 6, gently insert the fiber into the connector and put the connector components together.
  • Step 7, place the connector in the polishing disk. Put it on the polishing film, and lightly polish the connector for 8 to 10 times.
  • Step 8, mission complete! Give it a try on your equipment.

fiber-optic-termination

Conclusion

Bare fiber terminated with fiber optic connectors greatly eases the stress for cable installation. It is always recommended to turn to the professionals for help when doing fiber optic termination.

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.

An Alternative Reading of Fiber Optic Connector

Being a part of the fiber patch cable, the fiber optic connector is utilized to achieve accurate and precise connections of the fiber ends. Now there are many kinds of fiber optic connectors in the market, such as ST, FC, SC, LC and so on (as shown in the following figure). Since the fiber cable transmits pulses of light instead of electrical signals, it is important to choose a good fiber optic connector that aligns microscopic glass fibers perfectly in order to allow for communication. This post will introduce fiber optic connector in an alternative way.

Optical-connectors1
Structure of Fiber Optic Connector

Though the mechanical design varies a lot among different connector types, the most common elements in a fiber connector can be similar. That’s to say, the connector is mainly composed of fiber ferrule, connector sub-assembly body, connector housing, fiber cable and stress relief boot. The following figure takes SC connector as example to show the general components of the connectors.

SC connector
Typical Types of Fiber Optic Connector

Different kinds of optical fiber cables may need different connectors. Seen from the types of optical fiber, the fiber optic connectors may be loosely classified into standard fiber optic connectors, small form factor fiber optic connectors and ribbon fiber connectors. These family types of fiber connectors sometimes may overlap with each other.

Standard Fiber Optic Connectors

Generally having a ferrule of 2.5mm, standard fiber optic connectors are connectors commonly used in the fiber network. They can be both simplex and duplex and available in single mode and multi-mode fibers. ST, FC, SC, FDDI and ESCON are all standard fiber connectors. But they also differ from each other. ST connector is the most popular connector for multi-mode fiber optic LAN applications. FC connector is specifically designed for telecommunication applications and provides non-optical disconnect performance. SC connector is widely used in single mode applications for its excellent performance. FDDI connector, which is a duplex multi-mode connector, utilizes two 2.5mm ferrules and is designed to used in FDDI network. ESCON connectors are similar to FDDI connectors, but contain a retractable shroud instead of a fixed shroud.

Small Form Factor Fiber Optic Connectors

To meet the demand for devices that can fit into tight spaces and allow denser packing of connections, a number of small form factor fiber optic connectors have been developed since the 1990s. In this type of small form factor fiber optic connectors, some are miniaturized versions of older connectors, built around a 1.25mm ferrule rather than the 2.5mm ferrule. For example, the LC, MU, E2000 connectors. While the others are based on smaller versions of MT-type ferrule for multi-mode fiber connections, or other brand new designs. For example, the MT-RJ connector, which has a miniature two-fiber ferrule with two guide pins parallel to the fibers on the outside. Its overall size is about the same as a RJ45 connector.

Ribbon Fiber Connectors

MTP and MPO are compatible ribbon fiber connectors based on MT ferrules which allow quick and reliable connections for up to 12 fibers. Since the MTP product complies with the MPO standard, the MTP connector is an MPO connector. Along with the MTP patch cables (for example, MTP-MTP fiber trunk cable), MTP connectors can upgrade the 10G network to 40G/100G.

Conclusion

The fiber optic connector is an essential part in fiber optical network. As the popularity of fiber optical network, about 100 fiber optic connectors have been introduced to the market. FS.COM is the main professional fiber optic products supplier in China, and we offers various kinds of fiber cable connectors, especially the commonly used FC, LC, SC, ST and MPO connectors.

Fiber Optic Connector Cleaning

With the deployment of 40G and 100G systems in the data center, reliable and efficient fiber installations are critical to the high performance network. Contaminated fiber optic connectors can often lead to degraded performance. Any contamination on the fiber connectors can cause failure of the component or failure of the whole system. So it’s important to keep fiber connectors clean.

Contamination Sources

There are two most important forms of contamination on fiber connectors and they are oils and dust. Oils from human hands will leave a noticeable defect easily seen with a fiberscope. The oil will trap dust against the fiber and bring scratches to the fiber connector. Inserting and removing a fiber can create a small static charge on the ends, which can attract airborne dust particles. Simply removing and re-inserting a fiber may also contaminate the end of the connector with a higher level of dust. Fiber caps, which are used to prevent fiber ends from being contaminated while not seated in a connector, will collect dust, dirt, oil and other contaminants to the fiber when used. Except oil and dust, there also other types of contamination, such as film residues condensed from vapors in the air, powdery coatings leaving after water or other solvents evaporating away. These contaminates tend to more difficult to remove and can also cause damage to equipment if not removed.

Contamination Inspection Tools

To inspect whether a fiber connector is contaminated, one should use fiberscope, clean and resealable container for the endcaps, bulkhead probe. A fiberscope is a customized microscope for inspecting optical fiber components. The fiberscope should provide at least 200x total magnification. The bulkhead probe is a handheld fiberscope used in order to inspect connectors in a bulkhead, backplane, or receptacle port. It should provide at least 200x total magnification displayed on a video monitor.

Contamination Inspection Steps

With contamination inspection tools, you should know how to inspect fiber connectors. The following introduces the inspection steps:

  • Make sure that the lasers are turned off before you begin the inspection. Be careful: Invisible laser radiation might be emitted from disconnected fibers or connectors. Do not stare into beams or view directly with optical instruments.
  • Remove the protective cap and store it in a clean resealable container. Verify the style of connector you inspect and put the appropriate inspection adapter or probe on your equipment.
  • Insert the fiber connector into the fiberscope adapter, and adjust the focus ring so that you see a clear end-face image. Or, place the tip of the handheld probe into the bulkhead connector and adjust the focus.
  • On the video monitor, see if there is contamination present on the connector end-face (See the following figure).

fiber optic connector before and after cleaning

Connector Cleaning Tools

If there is contamination inspected on the fiber connector, then you need to clean it with proper tools. These tools can be divided into four types based on the cleaning method.

one push cleaner

  • Wet cleaning: Optic cleaning with a solvent.
  • Non-Abrasive cleaning: Cleaning without abrasive material touching the fiber optic connector end face.
  • Abrasive cleaning: The popular lint free wipes, such as fiber optic mini foam swabs.
Connector Cleaning Steps

How to clean the fiber connector? Here is about the cleaning steps with abrasive cleaning tools.

  • Gently wipe end-face with lint-free pad in one direction.
  • Using a can with compressed gas held upright and approximately 2 inches from the connector end, release a stream of gas on the connector end-face for no more than 5 seconds.
  • Gently wipe the ferrule and the end-face surface of the connector with an alcohol pad. Making sure the pad makes full contact with the end-face surface. Wait 5 seconds for the surface to dry.

After finishing the cleaning steps, you should better inspect again to make sure there is definitely no contamination on the connector. Remember never touch the end face of the fiber connector and always install dust caps on unplugged fiber optic connectors. Do not re-use optic cleaning swabs or lens paper (lint free wipes).

Source: Fiber Optic Connector Cleaning

Fiber Optic Cable and Connector Selection

Proper selection of fiber optic cables and connectors for specific uses is becoming more and more important as fiber optic systems become the transmission medium for communications and aircraft applications, and even antenna links. Choices must be made in selecting fiber optic cables and connectors for high-reliability applications. This article provides the knowledge for how to make appropriate selections of fiber optic cable and connector when designing a fiber optic system.

Fiber Optic Cable Selection

To select a fiber optic cable, you have to make choices of both the fiber selection and the cable construction selection.

Fiber Selection

The three major fiber parameters used in selecting the proper fiber for an application are bandwidth, attenuation and core diameter.

Bandwidth: The bandwidth at a specified wavelength represents the highest sinusoidal light modulation frequency that can be transmitted through a length of fiber with an optical signal power loss equal to 50 percent of the zero modulation frequency component. The bandwidth is expressed in megahertz over a kilometer length (MHz/km).

Attenuation: The optical attenuation denotes the amount of optical power lost due to absorption and scattering of optical radiation at a specified wavelength in a length of fiber. It is expressed as an attenuation in decibels of optical power per kilometer (dB/km). The attenuation is determined by launching a narrow spectral band of light into the full length of fiber and measuring the transmitted intensity.

Core Diameter: The fiber core is the central region of an optical fiber whose refractive index is higher than that of the fiber cladding. Various core diameters are available to permit the most efficient coupling of light from commercially available light sources, such as laser diodes. There are two basic fiber types, single-mode and multimode. Single-mode fiber has a core diameter of 8 to 10 microns and is normally used for long distance requirements and high-bandwidth applications. Multimode fiber has a core diameter of 50 or 62.5 microns and is usually used in buildings. The picture below shows single-mode and multimode fiber with different core diameters.

multimode and singlemode fiber

Cable Construction Selection

Another important consideration when specifying optical fiber cable is the cable construction. There are three main types of cable configurations: buffered fiber cable, simplex cable and multichannel cable.

Buffered Fiber Cable: There are two kinds of buffered fiber. The first is a loose buffer tube construction where the fiber is contained in a water-blocked polymer tube that has an inner diameter considerably larger than the fiber itself. The loose buffer tube construction offers lower cable attenuation from a given fiber, and a high level of isolation from external forces. Loose buffer cables are typically used in outdoor applications and can accommodate the changes in external conditions. The second is a tight buffer tube design. A thick buffer coating is placed directly on the fiber. The tight buffer construction permits smaller, lighter weight designs and generally yields a more flexible cable. A comparison of these two cable constructions is shown below.

Buffered Fiber

Simplex Cable: A simplex fiber optic cable has only one tight buffered optical fiber inside the cable jackets. Simplex fiber optic cables are typically categorized as interconnect cables and are used to make interconnections in front of the patch panel. They are designed for production termination where consistency and uniformity are vital for fast and efficient operation.

Multichannel Cable: Building multiple fibers into one cable creates a multichannel cable. This type of cable is usually built with either a central or external strength member and fiber bundled around or within the strength member. An external jacket is used to keep the cable together.

Fiber Optic Connector Selection

Connector is an integral component of the cabling system infrastructure, which keeps the information flowing from cable to cable or cable to device. There are various connector types, including LC, FC, ST, SC, MTRJ, MPO, MTP, DIN, E2000, MU, etc. To design a fiber optic system, optical connector selection is also a very important decision. When selecting an optical connector, you have to take polishing styles, fiber types and number of fibers all into consideration.

Polishing Styles: There are mainly three kinds of polishing styles, PC (physical contact), APC (angled physical contact), and UPC (ultra physical contact). PC, UPC and APC refer to how the ferrule of the fiber optic connectors is polished. PC connector is used in many applications. UPC connectors are often used in digital, CATV, and telephony systems. APC connectors are preferred for CATV and analog systems. The picture below shows these three kinds of polishing styles.

Polish Types

Fiber Types: Single-mode and multi-mode optical fiber are two commonly used fiber types. Accordingly, there are single-mode optical connector and multi-mode optical connector. ST and MTRJ are the popular connectors for multi-mode networks. LC connector and SC connector are widely used in single-mode systems. Single-mode fiber optic connectors can be with PC, or UPC or APC polish, while multi-mode fiber optic connectors only with PC or UPC polish.

Number of Fibers: Simplex connector means only one fiber is terminated in the connector. Simplex connectors include FC, ST, SC, LC, MU and SMA. Duplex connector means two fibers are terminated in the connector. Duplex connectors include SC, LC, MU and MTRJ. Multiple fiber connector means more than two fibers are terminated in the connector. These are usually ribbon fibers with fiber count of 4, 6, 8, 12 and 24. The most popular ribbon fiber connector is MT connector.

Conclusion

The key to designing a successful fiber optic system is understanding the performance and applications of different kinds of fibers, cable constructions and optical connectors, and then utilizing the appropriate components. Fiberstore provides a wide range of fiber optic cables and connectors. Fiber optic cables can be available in single-mode, multimode, or polarization maintaining, and they can meet the strength and flexibility required for today’s fiber interconnect applications.

LC Connector Introduction

Fiber optic connectors are used to the mechanical and optical means for cross connecting fibers. Fiber optic connectors can also be used to join fiber cables to transmitters or receivers. There have been many types of connectors developed for fiber cable. Single mode networks have used FC or SC connectors in about the same proportion as ST and SC in multimode installations. But LC connector with smaller size and higher performance has become popular and the connector choice for optical transceivers for systems operating at gigabit speeds. The following text gives a detailed introduction of LC connector.

History of LC Connector

LC stands for Lucent Connector, as the LC connector was developed by Lucent Technologies as a response to the need by their primary customers, the telcos, for a small, low insertion loss connector. Then the LC design was standardized in EIA/TIA-604-10 and is offered by other manufacturers.

SC connector and LC connector

Advantages of LC Connector

There are solid reasons that the LC is the preferred connector for high-performance network. From the appearance, LC connect is like a mini size of SC connector. LC connector borrows split-sleeve construction and a cylindrical ferrule (usually ceramic) from SC connector. LC connector has a push-and-latch design providing pull-proof stability in system rack mounts. The picture on the right shows the appearance of SC connector and LC connector.

The ferrule size of LC connector is 1.25 mm which is half the size of SC connector ferrule—2.5 mm. LC connector is rated for 500 mating cycles and its typical insertion loss is 0.25 dB. An interesting feature of the LC is that, in some designs, the ferrule can be “tuned” or rotated with a special tool after it has been assembled. This offers a considerable performance advantage. The design and performance of LC connector address the need for high density and low insertion loss.

Application of LC Connector

LC connector can be found in many places for termination and connection, especially SFP transceivers for gigabit transmission. For example, the optic interfaces of Cisco SFP transceivers are all LC connectors. Some other applications are as following:

Simplex and duplex LC connectors

  • Telecommunication networks
  • Local area networks
  • Data processing networks
  • Cable television
  • Fiber-to-the-home
  • Premises distribution
LC Connector Selection Guide

To meet the needs of market, there are various types of LC connectors provided now. During the selection of LC connector, transmission media should be the first factor to consider. LC connector favors single mode fiber optic cable. But it can also be used with multimode fiber optic cable. Signals sometimes are transferred over simplex fiber optic cable and sometime duplex fiber optic cable. Thus, LC connector has both simplex and duplex design. The picture above shows an APC simplex LC connector on the left and a UPC duplex LC connector on the right. Some other factors like polishing style (APC or UPC), hole size and cable diameter should not be ignored. For more details about LC connectors, you can visit Fiberstore which provides various LC connectors with high performance and low price.

Introduction of PC, UPC and APC Connector

When we choosing a LC connectors, you might hear descriptions like LC UPC polished fiber optic connector, or LC APC fiber optic connector. Or when you are choosing a ST fiber optic patch cable, you can find the description like ST/PC multimode fiber optic patch cable. What do PC, UPC, APC stand for? The following text will give the explanations.

fiber optic connector ferrule

PC (physical contact), UPC (ultra physical contact) and APC (angle physical contact) are the polish style of ferrules inside the fiber optic connectors. Unlike copper cables with copper wire in the connectors as connection media, fiber optic connectors are with ceramic ferrules for connection. The picture on the left shows the ferrule in fiber optic connector. Different fiber optic connectors has different ferrule size and length. Also their polish style might be different.

To better understand the why we have PC, UPC and APC, let’s start with the original fiber optic connector which has a flat-surface and is also known as flat connector (showed in the following picture). When two flat fiber connectors are mated, an air gap naturally forms between the two surfaces from small imperfections in the flat surfaces. The back reflection in flat connectors is about -14 dB or roughly 4%. To solve this problem, the PC connectors came into being.

flat fiber connector

In the PC connector, the two fibers meet, as they do with the flat connector, but the end faces are polished to be slightly curved or spherical. This eliminates the air gap and forces the fibers into contact. The back reflection is about -40 dB. The following picture shows two end faces of PC connectors.

PC connector

UPC connector, usually has a blue-colored body, is an improvement to the PC connector with a better surface finish (as showed in the following picture) by an extended polishing. The back reflection of UPC connector is about -55 dB which lower than that of a standard PC connector. UPC connectors are often used in digital, CATV and telephony systems.UPC connector

PC and UPC connectors have reliable, low insertion losses. However, their back reflection depends on the surface finish of the fiber. The better the fiber gain structure, the lower the back reflection. If the PC and UPC connectors are continually mated and remated, back reflection will degrade. An APC connector won’t have such problem. Its back reflection does not degrade with repeated matings.

APC connector

APC connector usually has a green body with an end-face still curved but are angled at an industry-standard 8 degrees (showed in the above picture) which allows for even tight connections and smaller end-face radii. Thus any light that is redirected back towards the source is actually reflected out into the fiber cladding, again by virtue of the 8 degree angled end-face. APC ferrules offer return losses of -65dB. Some applications that are more sensitive to return loss than others that call for APC connectors, like FTTx and Radio Frequency (RF) applications. APC connectors are also commonly used in passive optical applications due to the fact that many of these systems also use RF signals to deliver video.

APC connector and UPC connector

PC, UPC or APC, which should be the choice of fiber optic connector? The answer is it depends. Choosing the appropriate connector for a fiber network depends on things such as, network design and function. Fiberstore offers a wide range of fiber optic connector as well as professional optical network solution. For more information you can visit Fiberstore.