Patent ID: 8174756

Claim:
An optical demodulator comprising: a first non-polarizing beam-splitting surface in a first optical structure having a first reflective surface parallel to the non-polarizing first beam-splitting surface; a cavity defined by a first plate in optical contact with an exit face of said first optical structure, a spacer, and a second plate; a second non-polarizing beam-splitting surface in a second optical structure having a second reflective surface parallel to the second non-polarizing beam-splitting surface, said second optical structure having an entry face in optical contact with said second optical plate; and a phase tuner in an optical path of said demodulator; a delay element in said cavity to produce a desired phase delay; wherein a reflection beam produced by said first non-polarizing beam-splitting surface is reflected by the first reflective surface and directed through the optical cavity to impinge on the second non-polarizing beam-splitting surface, and a transmission beam produced by said first non-polarizing beam-splitting surface is directed through the optical cavity to impinge on the second reflective surface; and wherein said second reflective surface and said second non-polarizing beam-splitting surface are positioned such that said reflection and transmission beams interfere.