Chip-scale mid-IR scanning frequency modulated coherent ladar receiver

A coherent frequency modulated LADAR for emitting and detecting reflected optical signals, the LADAR comprising;

• a. an electrically controllable optical beam scanner receiving optical input beams arriving at different angles in a field of view of said electrically controllable optical beam scanner, said electrically controllable optical beam scanner conveying a scanned optical input beam as an output or reflected optical beam;
• b. a grating coupler responsive to the output or reflected optical beam of said electrically controllable optical beam scanner, said grating coupler having a waveguided output;
• c. an optical local oscillator laser having a waveguided output;
• d. a FMCW signal generator;
• e. an optical modulator responsive to the optical waveguided outputs of the optical local oscillator laser and also to an electrical FMCW signal from the FMCW signal generator;
• and
• f. a pair of second order non-linear optical elements for frequency upconverting respective outputs of the optical modulator and the grating coupler.

A method of detecting optical signals comprising:

• receiving optical input beams arriving at different angles in a field of view of an optical beam scanning device, the optical beam scanning device outputting or reflecting a scanned optical input beam as an output optical beam or as a reflected optical beam;
• providing an optical grating responsive to the output optical beam or the reflected optical beam of the optical beam scanning device, the optical grating providing a waveguided output;
• generating an optical local oscillator signal;
• generating a modulated electrical signal;
• modulating the optical local oscillator signal with the modulated electrical signal to generate a modulated optical local oscillator signal;
• mixing the frequency modulated optical local oscillator signal and the waveguided output of the optical grating;
• generating an electrical signal based on the results the mixing step.

An apparatus for detecting optical signals comprising:

• an optical beam scanner receiving optical input beams which arrive at different angles in a field of view of the optical beam scanner, the optical beam scanner outputting or reflecting a scanned optical input beam as an output optical beam or as a reflected optical beam;
• an optical grating responsive to the output optical beam or the reflected optical beam of the optical beam scanner, the optical grating providing a waveguided output;
• an optical local oscillator signal generator;
• a modulator for modulating the optical local oscillator signal with a modulated electrical signal to generate a modulated optical local oscillator signal;
• means for mixing the frequency modulated optical local oscillator signal and the waveguided output of the optical grating;
• generating an electrical signal from the mixing means.