An optical receiver comprising: a polarizing beamsplitter positioned along an optical axis to receive a free-space optical signal, the polarizing beamsplitter being configured to direct light having a first polarization along a first optical path and to direct light having a second polarization, orthogonal to the first polarization, along a second optical path; a first detector positioned along the first optical path to receive the free-space optical signal when the free-space optical signal has the first polarization; an alignment system configured to rotate either the optical receiver about the optical axis or a polarization of the free-space optical signal such that the free-space optical signal is directed along the second optical path; a faraday rotator positioned along the second optical path and configured to rotate the polarization of the free-space optical signal; an optical resonator configured to receive the free-space optical signal from the faraday rotator and to accumulate resonant optical signal energy, the optical resonator being configured to transmit first output optical signal energy from the optical resonator and reject second output optical signal energy from the optical resonator, wherein in response to a variation in the free-space optical signal corresponding to a modulation of the free-space optical signal, the optical resonator is configured to disrupt the first output optical signal energy and the second output optical signal energy to convert the modulation of the free-space optical signal into an intensity modulation of the first output optical signal energy and the second output optical signal energy; a second detector positioned to receive the first output optical signal energy and detect the intensity modulation of the first output optical signal energy; and a third detector positioned to receive the second output optical signal energy. a polarizing beamsplitter positioned along an optical axis to receive a free-space optical signal, the polarizing beamsplitter being configured to direct light having a first polarization along a first optical path and to direct light having a second polarization, orthogonal to the first polarization, along a second optical path; a first detector positioned along the first optical path to receive the free-space optical signal when the free-space optical signal has the first polarization; an alignment system configured to rotate either the optical receiver about the optical axis or a polarization of the free-space optical signal such that the free-space optical signal is directed along the second optical path; a faraday rotator positioned along the second optical path and configured to rotate the polarization of the free-space optical signal; an optical resonator configured to receive the free-space optical signal from the faraday rotator and to accumulate resonant optical signal energy, the optical resonator being configured to transmit first output optical signal energy from the optical resonator and reject second output optical signal energy from the optical resonator, wherein in response to a variation in the free-space optical signal corresponding to a modulation of the free-space optical signal, the optical resonator is configured to disrupt the first output optical signal energy and the second output optical signal energy to convert the modulation of the free-space optical signal into an intensity modulation of the first output optical signal energy and the second output optical signal energy; a second detector positioned to receive the first output optical signal energy and detect the intensity modulation of the first output optical signal energy; and a third detector positioned to receive the second output optical signal energy.