Fiber Connector Introduction

The optical fiber connector is a device for detachable (movable) connection between an optical fiber and an optical fiber. It precisely connects the two end faces of the optical fiber so that the light energy output by the transmitting fiber can be coupled to the receiving fiber to the maximum extent. And to minimize the impact on the system due to its intervention in the optical link, which is the basic requirement of optical fiber connectors. To a certain extent, the optical fiber connector also affects the reliability and performance of the optical transmission system.

Optical fiber connectors can be divided into common silicon-based optical fiber single-mode and multi-mode connectors according to different transmission media, as well as other optical fiber connectors such as plastics as transmission media; according to the structure of the connector, it can be divided into: FC , SC, ST, LC, D4, SMA 905, DIN, MU, MT, etc. various forms. Among them, ST connectors are usually used for wiring equipment, such as optical fiber distribution frames, optical modules, etc.; and SC and MT connectors are usually used for network equipment. According to the shape of the fiber end face, there are FC, PC (including SPC or UPC) and APC; according to the number of fiber cores, there are also single-core and multi-core (such as MT-RJ). Optical fiber connectors are widely used and have many varieties. In the actual application process, we generally distinguish according to the structure of the optical fiber connector.

Fiber optic connectors

FC round with thread (most used on patch panels)

ST snap-on round type

SC card-connected square type (most used on router switches)

PC microsphere grinding and polishing APC is 8 degree angle and do microsphere grinding and polishing

MT-RJ square type, a dual-fiber transceiver (useful on Huawei 8850)

Optical fiber module: generally supports hot swap, GBIC Giga Bit rate Interface Converter, the optical fiber interface used is mostly SC or ST type SFP small package GBIC, the optical fiber used is LC type.

Fiber Used: Single mode: L, wavelength 1310, single mode long distance LH, wavelength 1310, 1550 Multimode: MM wavelength 850.

SX/LH means single-mode or multi-mode fiber can be used.

In the label indicating the pigtail connector, we can often see "FC/PC", "SC/PC", etc., which have the following meanings The part in front of "/" indicates the connector model of the pigtail.

The SC connector is a standard square connector, using engineering plastics, which has the advantages of high temperature resistance and not easy to oxidize. The optical interface of the transmission equipment side generally uses the SC connector.

The LC connector is similar in shape to the SC connector, but smaller than the SC connector.

The FC connector is a metal connector, which is generally used on the ODF side. The metal connector can be plugged in more times than plastic.

There are many types of connector signals, in addition to the three introduced above, there are also MTRJ, ST, MU, etc.

For the specific appearance, see the following.

“/" indicates the cross-section process of the optical fiber connector, that is, the polishing method. "PC" is the most widely used in telecom operators' equipment, and its joint cross-section is flat. The attenuation of "UPC" is smaller than that of "PC", and it is generally used for equipment with special needs. Some foreign manufacturers use FC/UPC for internal fiber jumpers in ODF racks, mainly to improve ODF equipment's own indicators.

In addition, the "APC" model is widely used in radio and television and early CATV. Its pigtail head uses an end face with an angle, which can improve the quality of the TV signal. The main reason is that the TV signal is analog light modulation. When the connector is coupled When the surface is vertical, the reflected light returns along the original path. Since the unevenness of the refractive index distribution of the fiber will return to the coupling surface again, although the energy is small at this time, the analog signal cannot completely eliminate the noise, so it is equivalent to superimposing a weak signal with time delay on the original clear signal. It is ghosting on the screen. The inclination of the pigtail headband can prevent the reflected light from returning along the original path. Generally, this problem does not exist in general digital signals.