An apparatus comprising a plurality of laser transmitters each comprising a polarization rotator, a polarization rotator mirror coupled to the laser transmitters, and a multiplexer positioned between the laser transmitters and the polarization rotator mirror. Also included is an apparatus comprising a first rotator configured to rotate light polarization by about 45 or about −45 degrees, a second rotator configured to rotate light polarization by about 45 or about −45 degrees, a mirror coupled to one side of the second rotator and configured to reflect at least a portion of the light, and a wavelength division multiplexing (WDM) filter positioned between the first rotator and the second rotator.