Patent ID: 8559821

Claim:
A system comprising: a laser configured to generate a light having a wavelength and a polarization; an optical polarization rotator configured to rotate the polarization of the light; a photodetector configured to produce an electrical indication of the wavelength; at least one processor coupled to the photodetector and configured to: receive the electrical indication; determine a difference between the wavelength and a filter transmission peak; and adjust the laser to vary the wavelength, thereby reducing or substantially eliminating the difference and aligning the wavelength with the filter transmission peak; an arrayed waveguide grating (AWG) optically coupled to the optical polarization rotator such that the optical polarization rotator is positioned between the laser and the AWG; and a reflector coupled to the AWG such that the AWG is positioned between the optical polarization rotator and the reflector, wherein the reflector comprises: a first side facing the laser; a second side facing an optical network, wherein the second side comprises a partially reflective coating that is configured to allow some light from the laser to pass through the reflector; and a second optical polarization rotator coupled to the reflector such that the second optical polarization rotator is positioned between the first side of the reflector and the AWG and there are no optical components other than an optional optical fiber between the reflector and the second optical polarization rotator, and wherein there are no optical components other than either an optional optical fiber or an optional lens between the laser and the optical polarization rotator.