Three Common Methods for Fiber Optic Cable Termination

Fiber optic cable termination is the addition of connectors to each optical fiber in a cable. There is a common misunderstanding that fiber optic cable termination is time-consuming and highly specialized. With the development of termination technology, fiber termination systems now require less training and produce high quality fiber connections in less time than it takes to terminate coaxial cables. Generally, there are three common fiber termination methods available to installers: pre-polished connector systems, epoxy and polish fiber termination and splice-on pigtail connectors. This article will make a brief introduction of these termination methods for your reference.

Pre-polished Connector Systems

Many installers choose pre-polished connector systems for their fiber optic terminations. Fiber optic termination kits for modern pre-polished connector systems enable installers who have never worked with optical fiber, to become proficient at terminating fiber optic cables in a short amount of time. These fiber termination systems are ideal for installers who need to add connectors quickly when installing fiber optic equipment. This method does not require adhesives and polishing for field termination. Instead it uses a factory terminated connector with a stub fiber in the ferrule and a mechanical splice to terminate the fiber. Termination only requires preparing the cable, cleaving the fiber, inserting it in the connector and fixing it with a special tool. Insertion losses for modern fiber termination systems are approximately 0.2 dB, or a maximum of 0.5 dB for systems using a precision cleaver. However, the manufacturing process makes each connector more expensive and the good kits with quality cleavers are more expensive than polish fiber termination.

Epoxy and Polish Fiber Termination

When installing a complete, structured wiring system, many fiber installers prefer the epoxy and polish method of fiber termination. This process is more involved and requires bonding of the connector to the end of the fiber using an epoxy or anaerobic process. Once cured, the connector end is polished to a fine, flat surface. This method provides the lowest loss, greatest reliability, highest yield and the lowest cost of any termination type. For single-mode fiber, it is virtually the only method of termination that can provide the precise end finish necessary for the low loss and minimal reflectance required for high speed networks. While termination of multimode connectors is much less critical, especially where reflectance is concerned. One drawback to this method is that these additional steps of curing and polishing can increase the time required for installations. The following picture shows the fiber optic polishing machine used for this method.

Splice-on Pigtail Connectors

Splice-on connectors are an alternative to either the pre-polished connector systems or the epoxy method of termination. Fiber pigtails are usually built as fiber optic cable jumpers, either single-mode or multimode fiber jumpers, and then cut in two. A factory-polished connector with a fiber optic jumper is spliced onto the existing fiber using a fusion splicer. A splice tray and enclosure are used to protect the spliced fibers. The splice-on pigtail connectors combine the quality of fusion splicing, enabling technicians to use their existing equipment. This method allows technicians to run drop cables to an end user, cut off exactly the length they need, attach the splice-on connector, and plug it in. The splice-on connectors also enable technicians to manage exactly the cable weight they require without any shorts or excesses. The main drawback of this method is the cost of the connectors and the fusion splicing equipment. Also, specialized skills are needed to operate fiber splicing equipment.

Conclusion

Since the late 1970s, various fiber optic cable termination methods have been brought to market. The goal for each new termination method is to have better performance and be easier, faster, and less expensive. The above three fiber termination methods all have their advantages and disadvantages. After having a better understanding of these termination methods, you can select your termination method more easily.