Polarization based dual-mode optical transceiver

A method for transmitting an optical signal and detecting a back-reflected optical signal using an optical sensor, comprising:

• generating a coherent light signal;
• splitting the light signal using a power beam splitter and directing a portion of the light signal to a photonic mixer as a local oscillator signal, and directing another portion of the light signal to an input port of an optical transceiver;
• passing only a first polarization mode of the other portion of the light signal through the input port of the optical transceiver to a radiation area of the optical transceiver, and radiating the first polarization mode into space as a radiated light signal;
• directing the radiated light signal from the optical transceiver toward a target and directing a back-reflected light from the target to the optical transceiver, without altering polarization modes of the radiated light signal and the back-reflected light signal, wherein the back-reflected light signal contains both the first polarization mode and a second polarization mode, wherein the first and second polarization modes are two perpendicular linear polarization modes including a transverse electric (TE) mode and a transverse magnetic (TM) mode;
• capturing the back-reflected light signal by the radiation area of the optical transceiver, including both the first polarization mode and a second polarization mode;
• coupling only the second polarization mode of the captured light signal to an output port of the optical transceiver;
• directing the light signal from the output port of the optical transceiver into the photonic mixer;
• and
• coherently mixing the local oscillator signal and the received signals from the optical transceiver in the photonic mixer to generate In-phase and Quadrature-phase (IQ) signals.

A method for transmitting an optical signal and detecting a back-reflected optical signal using an optical sensor, comprising:

• generating a coherent light signal;
• splitting the light signal using a power beam splitter and directing a portion of the light signal to a photonic mixer as a local oscillator signal, and directing another portion of the light signal to a first port of a polarization beam splitter and rotator;
• the polarization beam splitter and rotator passing only the first polarization mode of the other portion of the light signal from the first port to a third port of the polarization beam splitter and rotator;
• an optical transceiver receiving the first polarization mode of the other portion of the light signal from the third port of the polarization beam splitter and rotator, and radiating the first polarization mode into space as a radiated light signal;
• directing the radiated light signal from the optical transceiver toward a target and directing a back-reflected light from the target to the optical transceiver, without altering polarization modes of the radiated light signal and the back-reflected light signal, wherein the back-reflected light signal contains both the first polarization mode and a second polarization mode, wherein the first and second polarization modes are two perpendicular linear polarization modes including a transverse electric (TE) mode and a transverse magnetic (TM) mode;
• capturing the back-reflected light signal by the radiation area of the optical transceiver, including both the first polarization mode and a second polarization mode;
• directing the captured light including both the first and the second polarization modes form the optical transceiver to the third port of the polarization beam splitter and rotator;
• the polarization beam splitter and rotator converting the second polarization mode of the received light signal on its third port to the first polarization mode and directing the converted light signal via its second port to the photonic mixer;
• and
• coherently mixing the local oscillator signal and the received signals from the optical transceiver in the photonic mixer to generate In-phase and Quadrature-phase (IQ) signals.