Phase-modulating communication device

A method of phase-modulated communication using a device with a reference path and a modulation path, the method comprising:

• retrieving calibration data from a memory of the device;
• applying a bias signal to one or more actuators of the device according to the calibration data;
• adjusting a length of the modulation path in response to the bias signal;
• receiving the communication signal at the device;
• directing a first part of the communication signal along the reference path and a second part of the communication signal along the modulation path;
• varying the length of the modulation path using the one or more actuators to create a phase difference between the second part of the communication signal and the first part of the communication signal;
• and
• reflecting the first part of the communication signal and the second part of the communication signal back along their respective reference path and modulation path away from the device.

A communication device, comprising:

• a housing having an aperture for receiving a communication signal;
• an optical arrangement disposed within the housing comprising a retro-optimized lens optically coupled with at least one reflector, the retro-optimized lens configured to minimize a deviation of a reflected signal from an incident path of the communication signal when the communication signal is reflected away from the communication device by the at least one reflector;
• and
• a phase modulator coupled to the optical arrangement and configured to selectively vary a phase of the reflected signal.

A phase-modulating retro-reflector, comprising:

• a housing having first and second apertures;
• a first lens optically coupled to the first aperture for receiving a first portion of an incoming communication signal;
• a first reflector optically coupled to the first lens and configured to reflect the first portion of the incoming communication signal along a reference path and toward a source of the communication signal;
• a second lens optically coupled to the second aperture for receiving a second portion of the incoming communication signal;
• a second reflector optically coupled to the second lens and configured to reflect the second portion of the incoming communication signal along a modulation path toward the source of the communication signal;
• an actuator configured to change a state of the second reflector so as to vary a length of the modulation path;
• and
• a processor coupled to the actuator for controlling a length of the modulation path in response to information from the second portion of the incoming communication signal.