Patent ID: 8320777

Claim:
A demodulator comprising: a. an optical beam splitter that splits a phase modulated optical signal into a first phase modulated optical signal propagating in a first optical path comprising free space and a second phase modulated optical signal propagating in a second optical path comprising a dielectric medium, the second phase modulated optical signal being delayed relative to the first phase modulated optical signal by a differential delay time that is proportional to at least one of a temperature and a refractive index of the dielectric medium; b. a temperature controller that is in thermal contact with the dielectric medium, the temperature controller changing a temperature of the dielectric medium to control at least one of a thermal expansion/contraction and a temperature dependent change in the refractive index of the dielectric medium, thereby changing the differential phase delay; and c. an optical beam splitter/combiner having a first input that is optically coupled to an output of the first optical path and a second input that is optically coupled to an output of the second optical path, a constructive output of the optical beam splitter/combiner generating a first demodulated optical signal and a destructive interference optical signal generating a second demodulated optical signal.