What is optical return loss?
For optical fibers, the loss typically happens at discontinuities of refractive index, such as splices or at an air-glass interface such as a fiber endface. This causes a fraction of the optical signal to be reflected back toward the source. The amount of reflection is determined by the Fresnel equations. Fiber optic transmission systems often use lasers to transmit signals over optical fiber. These can be sensitive to light returning into the component. A high optical return loss (ORL) can cause the laser to stop transmitting correctly.
