Patent ID: 8792155

Claim:
A demodulator, comprising: an input polarization beam splitter; a cubical polarization beam splitter positioned to receive an output from the input polarization beam splitter; an input half waveplate positioned between the input polarization beam splitter and the cubical polarization beam splitter; a first reflector positioned to receive and return a first output from the cubical polarization beam splitter; a first quarter waveplate positioned between the cubical polarization beam splitter and the first reflector; a second reflector positioned to receive and return a second output from the cubical polarization beam splitter; a second quarter waveplate positioned between the cubical polarization beam splitter and the second reflector; a beam displacer positioned to receive a third output from the cubical polarization beam splitter; an output polarization beam splitter positioned to receive an output from the beam displacer; an output half waveplate positioned between the beam displacer and the output polarization beam splitter; a wavelength tuner positioned between the second quarter waveplate and the cubical polarization beam splitter; and a redirecting element optically positioned between the cubical polarization beam splitter and the beam displacer and configured to redirect the third output from the cubical polarization beam splitter toward the beam displacer.