Temperature Controlled Interferometer For Phase Demodulation

An interferometer comprising:

• a. an optical beam splitter that splits an input optical signal into a first optical signal propagating in a first optical path comprising a first dielectric medium and a second optical signal propagating in a second optical path comprising a second dielectric medium, the second optical signal being delayed relative to the first optical signal by a differential delay time that is proportional to a difference in a refractive index of the first dielectric medium and a refractive index of a second dielectric medium;
• b. a temperature controller that is in thermal contact with the second dielectric medium, the temperature controller changing a temperature of the second dielectric medium to control at least one of a thermal expansion/contraction and a temperature dependent change in the refractive index of the second 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 first output of the optical beam splitter/combiner generating a first interferometric optical signal having an amplitude that is related to the differential delay and a second output of the optical beam splitter/combiner generating a second interferometric optical signal having an amplitude that is related to the differential delay.

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 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.

A method of demodulating a phase modulated optical signal, the method comprising:

• a. receiving a phase modulated optical signal;
• b. splitting the phase modulated optical signal into a first phase modulated optical signal propagating in a first optical path and a second phase modulated optical signal propagating in a second optical path comprising a dielectric medium;
• c. delaying the second phase modulated optical signal relative to the first phase modulated optical signal by a differential delay time which is determined by at least one of a temperature and a refractive index of the dielectric medium;
• and
• d. combining an output of the first optical path and an output of the second optical path, thereby generating a first demodulated optical signal and a second demodulated optical signal.