LC Connector Family

The LC connector developed by Lucent Technologies and shown in Fig.3.10 is a more evolutionary approach to achieving the goals of a SFF connector. The LC connector utilizes the traditional components of a SC duplex connector having independent ceramic ferrules and housings, with the overall size scaled down by one-half. The LC family of connectors includes a stand-alone simplex design; a “behind the wall” (BTW) connector and the duplex connector available in both single-mode and multimode tolerances are all designed using the RJ-style latch.

The outward appearance and physical size of the LC connector varies slightly depending on the application and vendor preference. Although all the connectors in the LC family have similar latch styles modeled after the copper RJ latch, the simplex version of the connector has a slightly longer body than either the duplex or BTW version, and the latch has an additional latch actuator arm that is designed to assist in plugging as well to prevent snagging in the field. The BTW connector is the smallest of the LC family and is designed as a field-or board-mounatable connector using 900-um buffered fiber and in some cases has slightly extended latch for extraction purposes. The duplex version of this connector has modified body to accept the duplexing clip that joins the two connector bodies toghther and actuates the two latches as one. Finally, even the duplex clip itself has variations depending on the vendor. In some cases the duplex clip us a solid one-piece design and must be placed on the cable prior to connectorization, while other design and must be placed on the cable prior to connectorization, while other designs have slots built into each side to allow the clip to be installed after connectorzation. In coclusion, all LC connectors are not created equal, and depending on style and manufacturer’s preference, there may be attributes that make one connector more suitable for a specific application then another.

The LC duplex connector incorporates two round ceramic ferrules with outer diameters of 1.25mm and a duplex pitch of 6.25mm. These ferrules are aligned through the traditional couplers and bores using precision ceramic split or solid sleeves. In an attempt to improve the optical performance to better than 0.10 db at these interfaces, most of the ferrule and backbane assemblies are designed to allow the cable manufacturer to tune them. Tuning of the LC connector simply consists of roating the ferrule to one of four available positions dictated by the backbone design. The concept is basically to align the concentricity offset of each ferrule to a single quadrant at 12.00; in effect, if all the cores are slightly offset in the same direction, the probalility of a core-to-core alignment is increased and optimum performance can be achieved. Although this concept has its merits, it is yet another costly step in the manufacturing process, and in the case where a tuned connector is mated with an untuned connector, the increase in performance may not be realized.

Typically, the LC duplex connectors are terminated onto a new reduced-size zipcord referred to as mini-zip. However, as the product matures and the applications expand, it may be found on a number of different cordages. The mini-zip cord is one of the smallest in the industry with an outer diameter of 1.6mm compared with the standard zipcord for an SC style product of 3.0 mm. Although this cable has passed industry standard testing, the cable manufacturers have raised some issues concering the ability of the 900-um fibers to move freely inside a 1.6-mm jacket and others involving the overall crimped pull strengths. For these reasons, some end users and calbe manufactures are opting for a larger 2.0-mm, 2.4-mm, or even the standard 3.0-mm zipcord. In application wher the fiber is either protected within a wall outlet or cabinet, the BTW connector is used and terminated directly onto the 900-um buffers with no jacket protection.

The factory termination of the LC cable assemblies is very similar to order ceramic-based ferrules using the standard pot and polish processes with a few minor differences. The one-piece design of the connector minimizes production handling and helps to increase process yields when compared with other SFF and standard connector types. Because of the smaller diameter ferrule, the polishing times for an LC ferrule may be slightly lower than the standard 2.5-mm connectors, but the real production advantage is realized in teh increase number of connectors that can be polished at one time in a mass polisher. For the reasons mentioned above and because the process is familiar to most manufacturers, the LC connector may be considered one of the eaisest SFF connectors to factory terminate.

Field termination of the LC connector has typically been accomplished through the standard pot and polish techiques using the BTW connector. However, a pre-polished, crimp and cleave connector is also available. The LCQuick Light field-mountable BTW style connector made by Lucent Technologies is a one-piece design with a factory polished ferrule and an internal cleaved fiber stub. Unlike other pre-polished SFF connectors previously discussed, the LCQuick light secures the inserted field cleaved fiber to a factory polished stub by crimping or collapsing the metallic entry tube onto the buffered portion. This is accomplished by using a special crimp tool that is designed not to damage the fibers. However, light is designed specifically for use in protected environments such as cabinets and wall outlets and has no provision for outer jacket or Kevlar protection.

LC connections allow higher density applications based on its smaller diameter. The LC connection, commonly referred to as Lucent Connection, Little Connector or Local Connector, is commonly used today for uplink modules and other devices. This connector is a “snap” type, has a ferrule diameter of 1.25mm and defined by IEC 61754-20. We offer LC fiber cables and lc lc cable, including single mode 9/125 and multimode 50/125, multimode 62.5/125, LC-LC, LC-SC, LC-ST, LC-MU, LC-MTRJ, LC-MPO, LC-MTP, LC-FC, OM1, OM2, OM3. Other types also available for custom design. Excellent quality and fast delivery.

The LC fiber patch cable cable is with a small form factor (SFF) connector and is ideal for high density applications. The LC fiber patch connector has a zirconia ceramic ferrule measuring 1.25mm O.D. with either a PC or APC end face, and provides optimum insertion and return loss. The LC fiber patch cable connector is used on small diameter mini-cordage (1.6mm/2.0mm) as well as 3.0mm cable. LC fiber cable connectors are available in cable assembled or one piece connectors. The LC fiber optic assemblies family is Telcordia, ANSI/EIA/TIA and IEC compliant.

Parsing Fiber Optic Connectors

The network cabling industry’s fiber optic manufacturers over the last few decades have been on a constant mission to develop the better fiber connector. This means lower cost, lower dB losses, easier to terminate out in the field. There have been over 100 connectors developed over the years but a select few have stood the test of time and beat out their competition. Now, let’s talk about the most common fiber connectors as following:

A fiber optic connector terminates at the end of a fiber optic cable is used when you need a means to connect and disconnect the fiber cable quickly. A fiber splice would be used in a more permanent application. the connectors provide a mechanical connection for the two fiber cables and align both cores precisely so the light can pass through with little loss. There are many different types of connectors but many share similar features. Many connectors are spring loaded. This will push the fiber ends very close other so as to eliminate airspace between them, which would result in higher dB losses.

There are generally five main components to a fiber connector: the ferrule, the body, the coupling structure, the boot and the dust cap.

Ferrule: The ferrule is the small round cylinder that actually makes contact with the glass and holds it in place. These are commonly made of ceramic today but also are made of metal and plastic.

Body: This sub assembly holds the ferrule in place. It then fits into the connector housing.

Connector Housing: This holds all sub assembly parts in place and has the coupling that will connect to the customer’s equipment. The securing mechanism is usually bayonet, snap-in or screw on type.

Boot: This will cover the transition from the connector to the fiber optic cable. Provides stress relief.

Dust Cap: Just as it implies will protect the connector from accumulating dust.

There are many types of connectors on the market. The major differences are the dimensions and the method of connection to equipment. Most companies will settle on one type of connector and keep that as a standard across the board. It makes sense because all equipment has to be ordered with that specific connector type and to have 2 or 3 different connector types can get messy. For typical network cabling projects today LC is fast becoming the shining star of fiber connectors. LC is a small form factor connector which means it requires a much smaller footprint in your IT closet. Thus you can fit many more LC connectors into you fiber panels then say ST or SC connectors.

LC Connector

The LC connector was developed by Lucent Technologies, hence the LC. It is a Single Form Factor Connector that has a 1.25mm ferrule. The attaching mechanism is similar to an RJ-45 connector with the retaining clip. It is a smaller square connector, similar to the SC. LC connectors are often held together with a duplex plastic retainer. They are also very common in single mode fiber applications.

ST Connector

The ST connector was the first popular connector type to be used as a standard for many organizations in their fiber network applications. It has first developed by AT&T. Often called the “round connector” it has a spring loaded twist bayonet mount with a 2.5mm round ferrule and a round body. The ST connector is fast being replaced with the smaller, denser SFF connectors.

SC Connector

The SC connector is a push in/pull-out type connector that also has a 2.5 mm ferrule. It is very popular for its excellent performance record. The SC connector was standardized in TIA-568-A, and has been very popular for the last 15 years or so. It took a while to surpass the ST because of price and the fact that users were comfortable with the ST. Now it’s much more competitive with pricing and it is very easy install, only requiring a push in and pull out connection. This is very helpful in tight spaces. Simplex and duplex SC connectors are available. The SC was developed by the Japanese and some say stands for Standard Connector.

FC Connector

The FC connector you may find in older single mode installations. It was a popular choice that has been replaced by mostly ST or SC type connectors. It also has a 2.5mm ferrule. They have a screw on retaining mechanism but you need to be sure the key and slot on the connector are aligned correctly. FC connectors can also be mated to ST & SC’s through the use of an adaptor.

MT-RJ Connector

MTRJ stands for Mechanical-Transfer Registered Jack and was developed by Amp/Tyco and Corning. MTRJ is very similar to an RJ type modular plug. The connector is always found in duplex form. The body assembly of the connector is usually made from plastic and clips and locks into place. There are small pins present that guide the fiber for correct alignment. MTRJ’s also are available in male or female orientation. They are only used for multi-mode applications. They can also be difficult to test because many testers on the market do not accept a direct connection. You usually need to rig up a patch cord adaptor kit to make testing possible.

MU Connector

MU looks a miniature SC with a 1.25 mm ferrule. It’s more popular in Japan.

MT Connector

MT is a 12 fiber connector for ribbon cable. It’s main use is for preterminated cable assemblies and cabling systems. Here is a 12 fiber MT broken out into 12 STs.

MT connector is sometimes called a MTP or MPO connector which are commercial names.

Hopefully this guide may help you get an idea of what options are out there for your fiber optic connector needs.

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