Analysis of the Classification of Optical Fiber Connectors

Optical fiber connectors can be divided into common silicon-based optical fiber single-mode and multi-mode connectors according to different transmission media, and other optical fiber connectors such as plastic as the transmission medium; according to the structure of the connector, it can be divided into: FC , SC, ST, LC, MT and other forms. Here are some of the fiber optic connectors that are now common:

FC type fiber optic connector

This connector was first developed by Japanese NTT. FC is the abbreviation of Ferrule Connector, indicating that its external reinforcement method is a metal sleeve, and the fastening method is a turnbuckle. The earliest, FC type connector, the mating end face of the ceramic pin used is the plane contact method (FC). This type of connector is simple in structure, convenient in operation and easy to manufacture, but the fiber end is more sensitive to dust, and is prone to Fresnel reflection, making it difficult to improve return loss performance. Later, this type of connector was improved, and the contact pin (PC) with spherical end face was adopted, and the external structure was not changed, so that the insertion loss and return loss performance were greatly improved.

SC type fiber optic connector

This is a fiber optic connector developed by Japan's NTT company. Its shell is rectangular, and the structure and dimensions of the pins and coupling sleeves used are exactly the same as those of the FC type. Among them, the end face of the pin is mostly PC or APC type grinding method; the fastening method is a plug-in latch type, without rotation. This type of connector is inexpensive, easy to plug and unplug, small fluctuation in insertion loss, high compressive strength, and high installation density.

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

Biconic Connector

The most representative product of this type of fiber optic connector was developed by Bell Labs in the United States. It consists of two precision-molded cylindrical plugs with frusto-conical ends and a double-conical plastic sleeve inside. The coupling assembly of the cylinder is composed. DIN47256 fiber optic connector This is a connector developed in Germany. The pins and coupling sleeves used in this connector have the same structural dimensions as the FC type, and the end face treatment adopts PC grinding. Compared with the FC type connector, its structure is more complicated, and there is a spring that controls the pressure in the internal metal structure, which can avoid damage to the end face due to excessive insertion pressure. In addition, the mechanical precision of this connector is high, so the insertion loss value is small.

MT-RJ type connector

MT-RJ started from the MT connector developed by NTT. It has the same latching mechanism as the RJ-45 type LAN electrical connector. It is aligned with the optical fiber through the guide pins installed on both sides of the small sleeve. The optical fiber on the end face of the connector is designed in a double-core (0.75mm interval) arrangement. It is the next-generation high-density optical fiber connector mainly used for data transmission.

LC type connector

The LC type connector is researched and developed by the famous Bell Institute, and is made of a modular jack (RJ) latch mechanism that is easy to operate. The size of the pins and sleeves used is half the size of ordinary SC, FC, etc., which is 1.25mm. This can increase the density of fiber optic connectors in the fiber optic distribution frame. Currently, in single-mode SFF, LC-type connectors have actually dominated, and the application in multi-mode is also growing rapidly.