System and method of optical scanning with detection of return signals using a star coupler

Apparatus for optical scanning, comprising:

• a star coupler in which an input waveguide array comprises an input signal waveguide and one or more additional input-side waveguides, and in which an output waveguide array comprises a plurality of output waveguides;
• and
• an array of optical antenna elements adapted for transmitting send signals and receiving return signals, in which each optical antenna element is optically coupled to a respective output waveguide, wherein:
• a respective phase shifter is conformed to controllably adjust a phase shift in each of the output waveguides, whereby a steerable send beam of transmitted light can be defined;
• the input signal waveguide is adapted to receive an input beam of light from a light source in order for said input beam of light to be distributed by the star coupler into the array of output waveguides;
• and
• a respective optical detector is optically coupled to each of the one or more additional input-side waveguides for detecting light from return signals that has reentered the star coupler through the output waveguides.