Polarization-diversity optical power supply

An apparatus for communicating optical signals modulated at a symbol rate, the apparatus comprising an optical power supply that comprises:

• a light source and an electronic controller connected to the light source to cause the light source to generate a first light output having a first optical frequency and a second light output having a second optical frequency different from the first optical frequency, each of the first and second light outputs being steady during a time interval that is significantly longer than one over the symbol rate;
• a polarization combiner connected to receive the first and second light outputs of the light source, and generate an optical output signal in which first and second mutually orthogonal polarization components carry light of the first and second light outputs, respectively;
• a transmit module that includes at least one optical modulator configured to modulate the optical output signal from the polarization combiner;
• and
• an optical fiber that includes one or more sections of non-polarization-maintaining fiber, in which the optical fiber is optically coupled between the polarization combiner and the transmit module, and the optical fiber is configured to transmit the optical output signal from the polarization combiner to the transmit module;
• wherein the transmit module comprises:
• a passive polarization splitter having an optical input port and first and second optical output ports, the optical input port being optically connected to receive the optical output signal from the polarization combiner having first and second polarization components, the first polarization component carrying light of the first optical frequency, the second polarization component carrying light of the second optical frequency;
• wherein the first and second polarization components are mutually orthogonal and jointly undergoing a state-of-polarization change during a time interval, the passive polarization splitter causing light of a first fixed polarization to be directed from the optical input port to the first optical output port and also causing light of a second fixed polarization to be directed from the optical input port to the second optical output port, the first and second fixed polarizations being orthogonal to one another, the state-of-polarization change causing respective spectral compositions of the lights directed to the first and second optical ports to change during the time interval;
• and
• a first optical modulator optically coupled to the first optical output port and configured to modulate the light of the first fixed polarization received therefrom in response to a first data signal.