Reflectance

Reflectance is a measure of the light reflected from the cleaved or polished fiber end at the glass/air interface.  Reflectance is expressed in dB relative to the incident signal.  Reflectance is important in optical systems because some active optical components are sensitive to light reflected into them.  Reflected light is also a source of loss.  Also known as “backreflection,” and “optical return loss.”

See also: insertion loss, attenuation