Analysis of Optical Fiber Connector and its application, performance and terminal requirements (1)

In this article, we will introduce the user's optical fiber connector (SC), straight-through optical fiber connector (ST), fixed Optical Fiber Connector (FC) and LC optical fiber connector and their application, performance and terminal requirements. Unlike the BNC connector widely used in the/V industry, fiber optic connectors gradually develop with the maturity of fiber technology. Copper connectors generally do not have a significant impact on signal loss in the AV system, while optical fiber connections do not. They have a significant impact on each interface in the transmission system. Let's take a look at some problems arising from the physical connection of optical fiber. The optical fiber transmission device itself can be connected with commands, but in some cases, most or almost all optical fiber transmission connections are manually selected. The semaphores lost during the signal transmission of optical fiber cables are mainly determined by the quality and type of the optical fiber cables used. Each connection end will produce a certain amount of signal loss. Depending on the type of the selected Optical Fiber Connector, the total amount of signal loss at the connection end may exceed the signal loss produced by the optical fiber cable itself.

Signal Loss Calculation

Like power supply, fiber optic power supply is usually measured in dB. In a copper circuit, the signal loss of the connector is basically "zero" in both digital and analog signals. That is to say, compared with the loss of the signal produced by the overall cable, ohm loss caused by connector contact resistance is usually negligible. In most fiber-optic installation systems, the opposite is true. In AV applications, signal loss of optical fiber cables smaller than 1000 feet is basically less. Multi-mode optical fiber dispersion becomes very important when the transmission is several kilometers away. Therefore, it is best to use a single-mode optical fiber with low signal loss. However, no matter whether it is short-distance transmission or long-distance transmission, each connector interface that contacts the transmission signal will produce a large amount of signal loss. Generally, the largest part of the signal loss occurs at the output end, the key to installing a set of good optical fiber connectors is to minimize the loss of interface signals between interconnected optical fiber cables, so as to keep the loss within a certain estimation range and provide stability for the long-term operation of the system. The loss of the connector interface signal is also measured in dB. Due to improper connection at the end of the optical fiber, interruption of the optical path may lead to a certain amount of signal loss. For example, poor optical fiber surface and non-parallel connection may also cause the signal loss rate to be much higher than the expected signal loss.

The development of high-speed laser optical fiber transmission brings new problems to the design of the End Face of the optical fiber terminal. At high transmission rates, face reflection becomes very serious. Special processing such as angle grinding or spherical grinding is required to reduce the loss rate. In terms of more accurate estimation of signal loss, the signal loss range of a normal connection port is approximately 0.1dB to a maximum of 1.5dB. Think about how many connection points are needed from the signal source to the signal distribution machine, router, and workstation. The more contacts there are, the faster the estimation of signal loss will increase, we also need to consider some unexpected situations.

Maintain normal system operation

In the design of the optical fiber system, the system can operate normally, which achieves very good results. In the system design, we need to consider some unexpected problems that may occur in the system, and make the system work properly. In system design, we should consider the worst possible situations of the system, and make corresponding plans to look forward to better operational results. Fiber Connector designers must keep this idea in mind. In system design, secure and stable system connections require smooth and square optical fiber ends. The connection between the end and the end must be accurate, accurate or even reach micron, one thousandth of a meter. The diameter of commonly used Multimode Optical Fiber ranges from 50-microns, while that of single-mode optical fiber is only 8-9 microns. Comparing this diameter with the diameter of a hair (17-180 microns), we can see that any slight error can cause catastrophic losses.

The optical fiber connection has strict requirements on the precision of the device, so the connector must be very clean. Fiber optic connectors and accessories are usually packed in a set. A fingerprint or external dust may seriously affect the performance of the connector, or even cause transmission failure. Therefore, when the connector is not connected, it should be saved in a clean protective cover.

During the connection, we should also wedge the Optical Fiber Connector. In all the current optical fiber connector designs, it is carried out through the "ferrule" to ensure that the connector is accurate during the matching. The optical fiber terminal is made a permanent component in the ring through viscose or crimping clamp. After the built-in optical fiber is inserted, the ferrule end is smoothed to provide a smooth interface for fiber connection of the connector. Ferrule is usually made of relatively hard materials such as ceramics, of course, can also be made of stainless steel, plastic or WC material, General ferrule diameter of SC, ST and FC is 2.5mm, the diameter of the general ring of LC is 1.25mm. As the functional characteristics of the ring can be produced according to the precision requirements, it becomes the primary and important determining feature of the optical fiber connector. Among the numerous connection covers, spring container connection rings ensure coaxial alignment between optical fiber and LED or laser sources.

With the development and application of technology, fiber optic connectors have also developed rapidly. There are about 12 or more fiber optic connectors on the market, each of which came into being to meet specific needs. Of course, there are also some technical restrictions. The current market trend is mainly towards the development of a moderately priced and compact connector mode, which can support the higher transmission density required by the new transmission distribution system. As expected by users, the continuous development of the telecom industry has also promoted the wide-area application of optical fiber, this is largely due to the rapidly growing demand for optical fiber connections for various types of communication and entertainment services.