Common Fiber Connector Models

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

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, D4, DIN, MU, MT and other forms. The following are some of the more common fiber optic connectors:

(1)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 connectors, used ceramic pins for mating ports. This type of connector is simple in structure, easy to operate, 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, using the contact pin (PC) with spherical end face, but the external structure was not changed, so that the insertion loss and return loss performance have been greatly improved.

(2) 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.

(3) 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 components of the cylinder are composed.

(4) 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 to control 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.

(5) 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.

(6) 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. At present, in the aspect of single-mode SFF, the LC type connector has actually occupied the dominant position, and the application in multi-mode has also grown rapidly.

(7) MU type connector

MU (Miniature unit Coupling) connector is the world's smallest single-core optical fiber connector developed by NTT based on the SC-type connector that is currently most used. The connector features a 1.25mm diameter sleeve and a self-retaining mechanism, which has the advantage of enabling high-density mounting. Utilizing MU's 1.25mm diameter sleeve, NTT has developed the MU connector series. They are available with receptacle type connectors (MU-A series) for fiber optic connection; backplane connectors with self-retaining mechanism (MU-B series) and simplified sockets for connecting LD/PD modules to plugs (MU-SR series) Wait. With the rapid development of optical fiber networks towards larger bandwidth and larger capacity and the wide application of DWDM technology, the demand for MU connectors will also increase rapidly.