Patent ID: 8073344

Claim:
A heterodyne transceiver, comprising: (1) a heterodyne receiver having: first and second laser sources operative to generate respective optical receiver oscillator (RO) signals having respective RO frequencies; temperature control circuitry operative to control a temperature difference between respective operating temperatures of the first and second laser sources such that the RO frequencies differ by a difference frequency corresponding to the temperature difference, the difference frequency being offset from a frequency of a modulated millimeter-wave signal by a predetermined intermediate frequency, the millimeter-wave signal being a return signal from a target, the return signal resulting from interaction of an incident millimeter-wave signal with the target; an electro-optical nonlinear mixer operative to receive the optical RO signals and the modulated millimeter-wave signal and generate an electrical intermediate-frequency (IF) signal having the predetermined intermediate frequency; and an electrical amplifier/detector operative to receive the electrical IF signal and generate an electrical detector output signal corresponding to the modulation of the modulated millimeter-wave signal; and (2) a heterodyne transmitter operative to generate the incident millimeter-wave signal, wherein the electrical IF signal is generated during a receive interval separate from a transmit interval during which the incident millimeter-wave signal is generated, and wherein the electro-optical nonlinear mixer is operative during the transmit interval to receive optical transmit oscillator (TO) signals to generate the incident millimeter-wave signal, the optical TO signals having respective TO frequencies differing by the frequency of the incident millimeter-wave signal.