Fiber optic jumpers, as an important link for interconnecting network devices, are currently the most widely used passive optical devices in optical communication. Among them, the performance of the connectors at both ends of the jumper directly affects the quality of optical transmission. Therefore, to ensure efficient signal transmission in the fiber optic link, two key optical performance indicators, insertion loss (IL) and return loss (RL), are usually used to evaluate it. This article will focus on discussing the main factors that affect the two types of losses and their optimization methods.
What is the insertion loss
In the field of telecommunications, insertion loss refers to the loss of signal power caused by the insertion of a certain device at a certain point in the transmission system, usually referred to as attenuation, used to represent the ratio of the output optical power of a port to the input optical power, in decibels (dB). Obviously, the lower the insertion loss value, the better the insertion loss performance.
What is the return loss
Echo loss refers to the power loss caused by the reflection of some signals back to the signal source during transmission due to the discontinuity of the transmission link. This discontinuity may be mismatched with the terminal load or with the devices inserted in the line. Echo loss is easily misunderstood as the loss caused by the echo. In fact, it refers to the loss of the echo itself, that is, the larger the echo is lost, the smaller the echo. It represents the ratio of the reflected wave power of the transmission line port to the incident wave power, in decibels, usually a positive value. Therefore, the higher the absolute value of echo loss, the smaller the reflection amount, and the greater the signal power transmission, i.e. the higher the RL value, the better the performance of the fiber optic connector.
Factors affecting insertion loss and return loss
A single fiber optic jumper directly connected is the most ideal fiber optic path, where the loss is minimized, i.e. a directly connected fiber optic with no interference between the ends of A and B. However, typically, fiber optic networks require connectors to achieve modularity and path segmentation. Therefore, the ideal low insertion loss and high return loss performance will be greatly compromised due to the following three reasons.
End face quality and cleanliness
Obviously, defects such as scratches, dents, cracks, and particle contamination on the fiber end face directly affect its performance, resulting in higher insertion loss and lower return loss. Any abnormal situation that hinders the transmission of optical signals between optical fibers will have a negative impact on these two types of losses.