Other possible issues include faulty fusion splices, misalignment, or incorrect polarity. Fiber optic cables are the backbone of modern communications, delivering high-speed data over long distances with minimal loss. However, in real-world installations, whether underground, aerial, or in harsh industrial environments, fiber cables can and do fail. Understanding the common causes of. Optical fiber coupling is the process of efficiently transferring light energy from one optical component into a receiving optical fiber, or between two separate fibers. This transfer involves channeling the light, which carries data, from a source such as a laser or LED directly into the hair-thin. The actual effects of misalignment are affected by the distribution of light in the fiber (mode power distribution). It's surprising but standard fiber specifications allow for up to +/-2. 5. In fact, contamination—including dust, fingerprints, and oily residues—is the leading cause of fiber failures, as it can lead to excessive signal loss or even permanent damage to the connector end faces. The table below shows how you can check. Problems within a fiber link can occur due to a wide variety of reasons.