Fiber Optic Connectors

Fiber optic connector

Fiber optic connector is a removable connection part between optical fiber and optical fiber, it puts the two surface of fiber with precision docking, so that the output light energy of the transmitting fiber can be maximally transferred to the receiving fiber, and minimize the effects on the system due to its interference to the optical link--which is the basic requirement of optical fiber connector.To some extent, fiber optic connectors also affect the reliability and performance of optical transmission systems.

Fiber optic connectors can be divided into the common single-mode and multi-mode connectors of silicon-based fiber according to the different transmission media. And other fiber optic connectors such as those that use plastic as the medium of transmission. According to the connector structure can be divided into: FC, SC,ST, LC, D4, DIN, MU, MT and other forms. Among them, ST connector is usually used for wiring equipment terminal, such as optical fiber distribution frame,optical fiber module, etc.; SC and MT connectors are typically used on network devices. FC, PC (including SPC or UPC) and APC according to the shape of fiberend face; single core and multi-core (such as MT-RJ) according to the fibercore number. Fiber optic connectors are widely used and of various varieties.In the practical application, they are divided according to the different structure of optical fiber connector. Here are some common fiber optic connectors:

(1) FC fiber optic connector

Abbreviation of Ferrule Connector. The connector was first developed by Japan's NTT, whichindicates that its external reinforcement is of the form of a metal sleeve withscrew fastening mode. This kind of connector is simple in structure, easy to operate and easy to make. But the optical fiber end is sensitive to dust andeasy to produce Fresnel reflection, so it is difficult to improve the performance of return loss. Later, this type of connector was improved by adopting a spherical pin (PC) on the butt surface, while the external structure was not changed, which greatly improved the performance of insertion loss and return loss.

(2) SC typefiber optic connector

This is a fiber optic connector developed by the Japanese company NTT. Its shell is rectangular, and the structure size of the plunger and coupling sleeve is exactly the same as FC type. PC or APC grinding mode is usually adopted for the end faces of the pins. Fastening method is plug and pull pin latch type, do notneed to rotate. This kind of connector has the advantages of low price, convenient operation, small fluctuation of insertion loss, high compressive strength and high installation density.

ST and SC interfaces are two types of fiber optic connectors. For 10 Base-F connections,the connector is usually ST type, and for 100 Base-FX, the connector is mostly SC. The core of ST connector is exposed, and the core of SC connector is inside the connector.

(3) Biconic Connector

The most representative product of this type of fiber optic connector is developed by Alcatel-Lucent Bell Labs in the United States. It consists of two precision molded tapered cylindrical plugs with truncated ends and a coupling assembly with a plastic sleeve with a double cone inside.

(4) DIN47256 optical fiber connector

This is aconnector developed in Germany. The structure size of the plunger and coupling sleeve adopted by this connector is the same as FC type. And the end face processing adopts PC grinding mode. Compared with FC connector, its structureis more complex. The internal metal structure has a pressure control spring, which can avoid the damage of the end face due to too much pressure plug. In addition, the mechanical precision of the connector is higher, so the insertion loss is small.

(5) MT-RJ connector

MT - RJ started in MT connectors developed by NTT. Wear the same latch mechanism of RJ-45 LANelectric connector. Alignment of the optical fiber with guide pins mounted onboth sides of the small sleeve for easy connection to the optical transceiver.The connector end face fiber is designed as a dual-core (0.75mm interval) arrangement, mainly used for data transmission for the next generation of high density optical fiber connector.

(6) LC connector

LC connector is developed by the famous Alcatel-Lucent Bell Labs and is made by the convenient modular jack (RJ) latch mechanism. The size of the inserted needle and sleeveis one half of the size of ordinary SC, FC, etc., which is 1.25mm. This increases the density of fiber optic connectors in the fiber distribution frame. At present, in terms of single-mode SFF, LC type connectors have actually occupied a dominant position, and their applications in multi-mode arealso growing rapidly.

(7) MU connector

MU (Miniatureunit Coupling) connector is based on the SC connector that has been used themost, and has been developed by NTT as the world's smallest single-core fiber connector. The connector uses a 1.25mm diameter casing and self-retaining mechanism, which has the advantage of high density installation. Using MU's l.25mm diameter casing, NTT has developed a MU connector family. They have socket connectors (MU-A series) for optical cable connections; baseplate connectors with self-retaining mechanism (MU-B series) and simplified sockets for connecting LD/PD modules to plugs (MU-SR series) etc. With the rapid development of fiber network to larger bandwidth and larger capacity and the wide application of DWDM technology, the demand for MU connector will also grow rapidly.