What is the result of poor mode coupling in multi-mode fibers?

Poor mode coupling in multi-mode fibers results in signal degradation. Multi-mode fibers are designed to carry multiple light modes simultaneously; however, inefficient mode coupling can lead to uneven distribution of light among the modes. This can cause certain modes to propagate slower than others or even lead to increased signal loss, thus degrading the overall signal quality. This degradation manifests as a reduction in the clarity of the transmitted data, impacting bandwidth and performance. The other options—such as increased signal clarity, reduced installation costs, and improved transmission speed—do not accurately reflect the consequences of poor mode coupling in multi-mode fiber optics, where the primary concern is the integrity and reliability of the transmitted signal.