Reflection loss

In telecommunications, reflection loss occurs on a line which results in part of the energy being reflected back to the source. This can occur:

1. At a discontinuity or impedance mismatch, e.g., in a transmission line, the ratio of the incident power to the reflected power. Reflection loss is usually expressed in dB.
2. In an optical fiber, the loss that takes place at any discontinuity of refractive index, especially at an air-glass interface such as a fiber endface, at which a fraction of the optical signal is reflected back toward the source. This reflection phenomenon is also called "Fresnel reflection loss," or simply "Fresnel loss."