Variable group delay compensating unit and variable group delay compensating module

摘要

A variable group delay unit has a light multiple reflector for receiving incident light and generating output light at varied output angles depending on wavelengths, a light returning part for returning the output light to the light multiple reflector, and a slit member which is provided between the light multiple reflector and the light returning part. Only light of a necessary degree is transmitted through the slit member and is reflected to a light reflecting element. A method for designing an opening width of the slit member and a method for arranging the slit member are established.