Classification of fiber optic connectors

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 the transmission medium; according to the structure of the connector, it is divided into: FC, SC , ST, LC, D4, DIN, MU, MT and other forms. Among them, ST connectors are usually used for wiring equipment, such as fiber distribution frames, fiber modules, etc.; while SC and MT connectors are usually used for network equipment.

According to the shape of the fiber end, there are FC, PC (including SPC or UPC) and APC; according to the number of fiber cores, there are single-core and multi-core (such as MT-RJ) points.

The optical fiber connector

1. FC type

This connector was first developed by Japanese NTT. FC is the abbreviation, indicating that the 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).

Such connectors are simple in structure, easy to operate, and easy to manufacture, but the fiber ends are more sensitive to dust, and are prone to Fresnel reflections, making it difficult to improve return loss performance. Later, an improvement was made to the new type of connector, using a pin (PC) with a spherical end face, but the external structure did not change, which greatly improved the insertion loss and return loss performance.

2. LC type

The LC type connector is researched and developed by the famous Bell Research Institute, and adopts the modular jack (RJ) door lock mechanism title with simple and convenient operation. 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 optical distribution frame. At present, in terms of single-mode SFF, LC-type connectors have actually occupied a dominant position, and the application in multi-mode is also growing rapidly.

3. SC type

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. The end faces of the pins are mostly ground by APC or APC type; rotate. 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.

4. MTRJ type

MT-RJ originates from the MT connector developed by NTT Company. Its shell and locking mechanism are similar to RJ. The optical fiber is aligned with the guide pins on both sides of the small sleeve. The double-core (0.75mm interval) arrangement design is a high-density optical connector mainly used for data transmission. The standard size MT-RJ type can connect two fibers at the same time, doubling the effective density.