What Is a Fiber-Optic Connector?

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

It is used to connect the optical fiber repeatedly, and it is also called the optical fiber active connector. The main performance parameters (and typical values) are: insertion loss (<0.5dB), repeatability of insertion and removal, and interchangeability between connectors (500 times change). When used for high-capacity high-speed transmission systems, small reflections are also required.

Introduction

Optical fiber connectors can be divided into common silicon-based optical fiber single-mode and multi-mode connectors according to the different transmission media, and there are other such as plastic

The main purpose of the optical fiber connector is to achieve the splicing of the optical fiber. Optical fiber connectors that have been widely used in optical fiber communication systems have many types and different structures. But on a closer look, the basic structure of various types of fiber optic connectors is the same, that is, most fiber optic connectors generally use high-precision components (consisting of two pins and a coupling tube consisting of three parts) Optical fiber alignment connection.

In this method, an optical fiber is inserted into and fixed in a pin, and the pin surface is polished to achieve alignment in a coupling tube. The outer component of the pin is made of metal or non-metal material. The mating end of the pin must be ground, and the other end usually uses a bending restriction member to support the optical fiber or optical fiber cable to relieve stress. The coupling tube is generally made of two halves of ceramic, bronze, and other composite, fastened cylindrical members. Most of them are equipped with metal or plastic flanges to facilitate the installation and fixation of the connector. In order to align the optical fibers as accurately as possible, the processing accuracy of pins and coupling tubes is very high.

The performance of an optical fiber connector is first of all optical performance. In addition, the interchangeability, repeatability, tensile strength, temperature, and number of insertions and withdrawals of the optical fiber connector must also be considered.

(1) Optical performance: The requirements for the optical performance of optical fiber connectors are mainly the two most basic parameters of insertion loss and return loss.

Insertion loss (Insertion Loss) is the connection loss, which refers to the loss of effective optical power of the link caused by the introduction of the connector. The smaller the insertion loss, the better. The general requirement should be no more than 0.5dB.

Return loss (ReturnLoss, ReflectionLoss) refers to the connector's ability to suppress the optical power reflection of the link, and its typical value should not be less than 25dB. In the practical application of the connector, the surface of the pin is specially polished, which can make the return loss greater, generally not less than 45dB.

(2) Interchangeability and repeatability

Optical fiber connectors are general-purpose passive components. For the same type of optical fiber connectors, they can generally be used in any combination and can be reused multiple times. The additional losses introduced are generally in the range of less than 0.2dB.

1. Optical fiber quick connector is a very innovative field termination connector. It contains factory-installed optical fibers, pre-researched and polished ceramic ferrules, and a mechanical connection mechanism.

2. When inserting the fiber, you only need to insert the introduced fiber or indoor fiber into the mechanical splicing mechanism. No other tools are needed. The termination process only takes about 2 minutes, which greatly saves installation time.

3. The ferrule and end face of the optical fiber quick connector are pre-polished and pre-polished before leaving the factory. The mechanical connection mechanism is located at the end of the ferrule to fix the inserted optical fiber.

4. The mechanical splicing mechanism is mainly composed of V-shaped grooves and clamping elements; when the optical fiber needs to be inserted, the V-shaped groove is opened with a wedge clamp to facilitate the smooth insertion of the optical fiber.

5. After the fiber is inserted into the V-groove and fixed, pull out the wedge clip from the V-groove. ^[3]

At present, with the continuous development of the domestic communication industry, optical fiber communication has entered the practical stage, and the scope of application is getting wider and wider. In China, the optical fiber connectors used in optical communication systems are either imported connectors, or imported so-called "bulk parts" such as ceramic sleeves and peripheral metal parts, or are assembled in China according to imported foreign technology The key equipment is produced, mainly FC type optical fiber connector. In view of this situation, the author recommends the following.

(1) Standardization issues

There are many types and standards of optical fiber connector products in the world. If there are no restrictions on the introduction and use, it will inevitably cause confusion and bring inconvenience to maintenance and management. According to reports, in this regard, the United States, Japan, Germany, France and other countries have national standards and recognized by the IEC; China also has similar regulations in this regard. It is recommended that such provisions be published in a national standard manner as a content in technical documents such as technical specifications or network access requirements.

(2) Compatibility issues

As communication is a system project, users are advised to consider the compatibility of optical fiber connectors used in optical transmission equipment, optical accessory equipment, optical test instruments and other items when ordering. On the basis of not affecting the performance of the system, the order of the instrumentation equipment should be the same as that of the optical fiber connector of the existing equipment. If not, you should consider the problems that may occur during use, and order or prepare the corresponding adapter flange or adapter.

(3) Production and use issues

As far as production is concerned, it is recommended that the country guide the manufacturers of fiber optic connectors to develop based on a core component (such as 2.5mm pins and corresponding sleeves) in accordance with relevant regulations and in combination with domestic existing and use conditions Develop products that meet national conditions and meet needs.

In terms of use, it is recommended that users should select the applicable fiber optic connector according to their actual situation. On the premise of meeting the system requirements, fully consider the relationship between performance, price and development, and strive to reduce costs and expand the scope of use. In future optical fiber user networks and high-speed local area networks, issues such as price and hardware upgrades may become more prominent, and users will need to comprehensively consider aspects such as performance, price and development. ^[4]