In the installation of any optical fiber system, we must consider the low loss method to connect the optical fiber or cable to each other, in order to realize the connection of optical link. The connection of optical fiber link can be divided into permanent and active. Permanent connection is mostly realized by fusion, bonding or fixed connector; Active connection is usually realized by active connector. This article will make a brief introduction of the activity connector.
Optical fiber movable connector, commonly known as movable connector, is a reusable passive device used to connect two optical fibers or optical cables to form a continuous optical path. It has been widely used in optical fiber transmission lines, optical fiber distribution frames, optical fiber test instruments and meters, and is the most used optical passive device at present.
The main purpose of optical fiber connector is to realize the connection of optical fiber. Nowadays, optical fiber connectors have been widely used in optical fiber communication system, with many kinds and different structures. But in detail, the basic structure of various types of optical fiber connectors is the same, that is, the vast majority of optical fiber connectors generally use high-precision components (composed of two pins and a coupling tube, a total of three parts) to achieve optical fiber alignment connection.
This method is to insert and fix the optical fiber in the pin, polish the surface of the pin, and then realize the alignment in the coupling tube. The outer component of the pin is made of metal or nonmetal materials. The butt end of the pin must be ground, and the other end is usually supported by a bending limiting member to release the stress. The coupling pipe is generally made of ceramic, or bronze and other materials, which are two half synthetic and fastening cylindrical components, and most of them are equipped with metal or plastic flange to facilitate the installation and fixation of the connector. In order to align the optical fiber as accurately as possible, the machining accuracy of the pin and coupling tube is very high.
The first performance of optical fiber connector is optical performance. In addition, interchangeability, repeatability, tensile strength, temperature and plugging times of optical fiber connector should be considered.
(1) Optical performance: for the optical performance requirements of optical fiber connector, the insertion loss and return loss are the two most basic parameters. Insertion loss refers to the loss of link effective optical power caused by the introduction of connector. The smaller the insertion loss, the better. Generally, it should be no more than 0.5dB. Return loss refers to the ability of the connector to suppress the reflection of link optical power, and its typical value should not be less than 25dB. For the practical connector, the surface of the pin has been specially polished, which can make the return loss greater, generally no less than 45dB.
(2) Interchangeability, repeatability, optical fiber connector is a common passive device, for the same type of optical fiber connector, generally can be used in any combination, and can be used repeatedly, resulting in the additional loss is generally less than 0.2db.
(3) Tensile strength: for the optical fiber connector, the tensile strength should not be less than 90N.
(4) Temperature, general requirements, optical fiber connector must be in – 40 ℃ ~ + 70 ℃ temperature can be used normally.
(5) At present, optical fiber connectors can be plugged more than 1000 times.