Patent ID: 8204384

Claim:
A phase-modulating communication device, comprising: a housing; a lens arrangement configured to pass a communication signal into the housing; a beam splitter optically coupled to the lens arrangement and configured to direct a first part of the communication signal along a reference path and a second part of the communication signal along a modulation path; a phase modulator configured to vary a length of the modulation path in relation to a length of the reference path responsive to a control signal; a photodetector configured to detect the communication signal and to output a receive data signal; a processor coupled to the phase modulator and the photodetector and configured to modulate the control signal based on the receive data signal; a first reflective element configured to reflect the first part of the communication signal along the reference path and toward a source of the communication signal; and a second reflective element configured to reflect the second part of the communication signal along the modulation path and toward the source of the communication signal.