An illumination module may provide light in a plurality of colors
including Red-Green-Blue (RGB) light and/or white light. The light from
the illumination module may be directed to a 3LCD system, a Digital Light
Processing (DLP.RTM.) system, a Liquid Crystal on Silicon (LCoS) system,
or other micro-display or micro-projection systems. In one embodiment the
illumination module includes a laser configured to produce an optical
beam at a first wavelength, a planar lightwave circuit coupled to the
laser and configured to guide the optical beam, and a waveguide optical
frequency converter coupled to the planar lightwave circuit and
configured to receive the optical beam at the first wavelength, convert
the optical beam at the first wavelength into an output optical beam at a
second wavelength, and may provide optically coupled feedback which is
nonlinearly dependent on a power of the optical beam at the first
wavelength to the laser.