An optical coupler helps split or join light signals in a fiber network. Their. What happens when light is injected into both input ports of a directional fiber coupler? How do high-power fiber couplers differ from standard couplers? What principles are used in high-power fiber couplers to minimize power losses? More questions. This is part 8 of a tutorial on passive fiber. 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. Fiber optic coupling sits right at the heart of modern spectroscopic instruments, letting us move light efficiently between a source, a sample, and a detector. It keeps the signal quality high while making instrument designs way more flexible and compact. A detector. Fibre optics is a terrestrial transmission medium in which, instead of electrical impulses travelling as in traditional copper networks, light impulses travel through a dielectric medium made of silicon glass.