1 Introduction
When installing any fiber optic system, it is necessary to consider connecting the fiber or fiber optic cable to each other in a low-loss manner to achieve the connection of the optical link. The connection of fiber links can be divided into two types: permanent and active. Permanent connections are mostly achieved by fusion bonding, bonding or fixed connectors; active connections are typically implemented using movable connectors. This article makes a brief introduction to the active connector.
Fiber optic connector, commonly known as a fiber optic connector, is commonly referred to as a fiber optic connector. It is a reusable passive device used to connect two fibers or cables to form a continuous optical path. It has been widely used in fiber transmission lines and fiber distribution frames. And optical fiber test instruments and meters are the most used optical passive components.
2. The general structure of the fiber optic connector
The main purpose of fiber optic connectors is to achieve fiber optic connections. Fiber connectors have been widely used in fiber-optic communication systems, and their types and structures are various. However, the basic structure of various types of fiber optic connectors is consistent, that is, most fiber optic connectors generally use high-precision components (composed of two pins and one coupling tube) to realize the fiber. Alignment of the connection.
In this method, the fiber is inserted into and fixed in the pin, and the surface of the pin is polished to achieve alignment in the coupling tube. The outer components of the pins are made of metal or non-metal materials. The butt end of the pin must be ground and the other end typically 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, fastened cylindrical members made of ceramic, or bronze, and is equipped with a metal or plastic flange to facilitate the mounting and fixing of the connector. In order to align the fiber as precisely as possible, the processing precision of the pin and the coupling tube is very high.
3. Performance of fiber optic connectors
The performance of fiber optic connectors is first of all optical performance, in addition to the interchangeability, repeatability, tensile strength, temperature and number of insertions and removals of fiber optic connectors.
(1) Optical performance: For the optical performance requirements of optical fiber connectors, the two most basic parameters of insertion loss and return loss are mainly used.
Insertion loss (InserTIon Loss), that is, connection loss, refers to the loss of effective optical power of the link due to the introduction of the connector. The smaller the insertion loss, the better. The general requirement should be no more than 0.5dB.
Return Loss refers to the connector's ability to suppress the optical power reflection of the link. Its typical value should be no less than 25dB. In practical applications, the pin surface is specially polished to make the return loss. Larger, generally no less than 45dB.
(2) interchangeability and repeatability
The fiber optic connector is a universal passive device. For the same type of fiber optic connector, it can be used in any combination and can be used repeatedly. Therefore, the additional loss introduced is generally less than 0.2 dB.
(3) Tensile strength
For a good fiber optic connector, the tensile strength is generally required to be no less than 90N.
(4) Temperature
Generally, fiber optic connectors must be able to operate at temperatures between -40 ° C and +70 ° C.
(5) Number of insertions and removals
Fiber optic connectors currently in use can generally be inserted and removed more than 1,000 times.
4. Some common fiber optic connectors
According to different classification methods, optical fiber connectors can be divided into different types. According to different transmission media, they can be divided into single-mode fiber connectors and multi-mode fiber connectors. According to different structures, they can be divided into FC, SC, ST, and D4. , DIN, Biconic, MU, LC, MT and other types; according to the pin end face of the connector can be divided into PC (UPC) and APC; according to the number of fiber cores, there are single core, multi-core.
In the actual application process, we generally distinguish according to the structure of the fiber optic connector. The following is a brief introduction to some of the more common fiber connectors:
(1) FC fiber optic connector
This connector was originally developed by NTT Japan. FC is an abbreviation of Ferrule Connector, which indicates that the external reinforcement method is a metal sleeve and the fastening method is a turnbuckle. At the earliest, FC type connectors, the mating end faces of the ceramic pins used were planar contact (FC). The connector has the advantages of simple structure, convenient operation and easy manufacture, but the fiber end face is sensitive to fine dust, and Fresnel reflection is easy to occur, and it is difficult to improve the return loss performance. Later, this type of connector was improved by using a pin (PC) with a spherical end face, and the external structure was not changed, so that the insertion loss and return loss performance were greatly improved.
(2) SC type optical fiber connector
This is a fiber optic connector developed by NTT Corporation of Japan. The outer casing has a rectangular shape, and the structure of the pin and the coupling sleeve is exactly the same as that of the FC type. The end face of the pin is mostly made of PC or APC type; the fastening method is plug-and-pull type, no need Rotate. These connectors are inexpensive, easy to insert and remove, have low insertion loss fluctuations, high compressive strength, and high installation density (most used on router switches).
(3) ST type optical fiber connector
ST type fiber jumper: commonly used in fiber distribution frame, the outer casing is round, and the fastening method is a turnbuckle. (For 10Base-F connections, the connector is usually ST type. Commonly used for fiber distribution frames)
(4) LC type optical fiber connector
The LC connector was developed by the famous Bell Institute and is manufactured using a convenient modular jack (RJ) latch mechanism. The size of the pins and sleeves used is half that of ordinary SC, FC, etc., which is 1.25 mm. This can increase the density of the fiber connectors in the optical distribution frame. At present, in the single-mode SFF, the LC type connector has actually occupied a dominant position, and the application in multi-mode has also grown rapidly.
(5) Double cone connector (Biconic Connector)
The most representative of these types of fiber optic connectors was developed by Bell Laboratories of the United States. It consists of two precision-molded ends with frusto-conical cylindrical plugs and a double-conical plastic sleeve inside. The coupling assembly of the barrel.
(6) DIN4 type optical fiber connector
This is a connector developed by Germany. The connector and coupling sleeve of this type of connector have the same structural dimensions as the FC type, and the end face processing adopts PC grinding. Compared with the FC type connector, the structure is more complicated, and the internal metal structure has a spring that controls the pressure, so as to avoid damage to the end surface due to excessive insertion pressure. In addition, the mechanical accuracy of such a connector is high, and the value of the insertion loss is small.
(7) MT-RJ type connector
MT-RJ started with the MT connector developed by NTT, with the same latching mechanism as the RJ-45 LAN electrical connector. The optical fiber is aligned with the guide pins mounted on both sides of the small sleeve for easy transmission and reception. The machine is connected, and the connector end face fiber is a double-core (interval 0.75mm) arrangement design, which 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 fiber optic connector developed by NTT based on the most widely used SC-type connector. The connector uses a 1.25mm diameter bushing and self-holding mechanism. Can achieve high density installation. Using MU's l.25mm diameter bushings, NTT has developed a series of MU connectors. They have socket type optical connectors (MU-A series) for fiber optic cable connection, backplane connectors with self-holding mechanism (MU-B series), and simplified sockets for connecting LD/PD modules and plugs (MU-SR series) )Wait. With the rapid development of fiber-optic networks to greater bandwidth and capacity, and the widespread use of DWDM technology, the demand for MU-type connectors will also grow rapidly.
ABB is a leading global engineering company that energizes the transformation of society and industry to achieve a more productive, sustainable future. By connecting software to its electrification, robotics, automation and motion portfolio, ABB pushes the boundaries of technology to drive performance to new levels. With a history of excellence stretching back more than 130 years, ABB's success is driven by 110,000 talented employees in over 100 countries.
Dc To Ac Converter,Inverter For Home ,Pure Sine Wave Inverter,Car Inverter
Wuxi Trenty Machinery & Equipment Co., Ltd. , https://www.elec-inverter.com