When installing any fiber optic system, a point that must be considered is how to connect optical fibers or optical cables to each other in a low-loss method to achieve optical link splicing. At this time, we have to understand one important thing - fiber optic connectors. So, what is the general structure of fiber optic connectors, and what are the common fiber optic connectors?
(1) What is the general structure of optical fiber connectors
The main purpose of fiber optic connectors is to connect optical fibers. Optical fiber connectors, which have been widely used in optical fiber communication systems, have many types and different structures. But on closer inspection, the basic structure of various types of fiber optic connectors is the same, that is, most fiber optic connectors generally use high-precision components (composed of three parts, two pins and a coupling tube) to realize optical fiber. alignment connection.
In this method, the optical fiber is inserted and fixed in the ferrule, and after the surface of the ferrule is polished, alignment is achieved in the coupling tube. The outer components of the pins are made of metal or non-metal materials. The butt end of the ferrule must be ground, and the other end usually uses a bend limiting member to support the fiber or fiber optic cable to relieve stress.
The coupling tube is generally made of two semi-synthetic and fastened cylindrical members made of ceramic or bronze and other materials, and is often equipped with a metal or plastic flange to facilitate the installation and fixation of the connector. In order to align the fibers as precisely as possible, the processing precision of the pins and coupling tubes is very high.
ZR Cable Fiber Connector
(2) What are the common fiber optic connectors
According to different classification methods, fiber optic connectors can be divided into different types. According to different transmission media, they can be divided into single-mode fiber optic connectors and multi-mode fiber optic connectors; according to different structures, they can be divided into FC, SC, ST, D4 , DIN, Biconic, MU, LC, MT and other types; according to the pin end face of the connector, it can be divided into PC (UPC) and APC; according to the number of fiber cores, there are single-core and multi-core points.
In the actual application process, we generally distinguish according to the structure of the optical fiber connector. The following is a brief introduction to some of the more common fiber optic connectors:
(1)FC fiber optic connector
This connector was first developed by ** 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 it is easy to produce Fresnel reflection, and it is difficult to improve the 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 performance of insertion loss and return loss was greatly improved.
(2) SC type fiber optic connector
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 PC or APC type; rotate. This type of connector is cheap, easy to plug and unplug, has small fluctuation in insertion loss, high compressive strength, and high installation density (the most used on router switches).
(3)ST type fiber optic connector
ST-type optical fiber jumper: commonly used in optical fiber distribution frame, the outer shell is round, and the fastening method is turnbuckle. (For 10Base-F connections, the connectors are usually ST type. Often used in fiber optic distribution frames)
(4) LC type fiber optic connector
The LC-type connector was developed by the famous Bell Research 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 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.
(5)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.
(6) DIN4 fiber optic connector
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.
(7) 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 connector mainly used for data transmission.
(8)MU type connector
The MU 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 adopts a 1.25mm diameter sleeve and a self-retaining mechanism. Its advantages lie in High-density installation is possible.
Using MU's 1.25mm diameter sleeve, NTT has developed a series of MU connectors. They are available as receptacle-type optical connectors (MU-A series) for fiber optic cable connection, backplane connectors with self-retaining mechanism (MU-B series), and simplified receptacles for connecting LD/PD modules to plugs (MU- SR series) etc. With the rapid development of fiber optic networks in the direction of larger bandwidth and larger capacity and the wide application of DWDM technology, the demand for MU-type connectors will also increase rapidly.
Regarding the relevant knowledge of optical fiber connectors, ZR Cable will first talk about it. In fact, with the continuous development of optical fiber communication technology, especially the development of high-speed local area networks and optical access networks, the application of optical fiber connectors in optical fiber systems will be more extensive. Of course, the requirements for optical fiber connectors will become higher and higher, especially for the performance requirements of optical fiber connectors.
