Generation of wideband high power coherent optical radar signals

Abstract

An arrangement for generating a high power optical radar beam. The arrangement includes first and second laser sources each having a first laser for generating an optical beam of a relatively low frequency Fand a second laser for generating an optical beam of relatively higher frequency F. Each laser source provides a first optical beam of frequency Fand a second optical beam of frequency F+F. The arrangement also includes first and second waveform generators each having a modulator and a mixer. A first waveform generator receives the optical beams from the first laser source and a modulation signal for modulating the F+Foptical beam. The first waveform generator is operative to provide an output optical beam of frequency Fhaving all of the modulation applied to the optical beam of frequency F+F. A phase comparator receives the outputs from the waveform generators and if they deviate in phase, a feedback device applies a corrective signal to the modulator of the second waveform generator until the two output signals are identical. When they are identical, the phase comparator is operable to provide an output optical beam which is the coherent addition of its two input optical beams.