Abstract: Aspects of the disclosure provide a method of adjusting a plurality of phase shifters of an OPA. The method may include identifying a plurality of subsets of phase shifters of the plurality of phase shifters based on an orthogonal set of functions; performing a plurality of dithers iteratively on the plurality of subsets of phase shifters of the plurality of phase shifters using the same frequency; determining a plurality of corrections based on a plurality of outputs of the OPA, each output resulting from each of the plurality of dithers; and adjusting the plurality of subsets of phase shifters of the plurality of phase shifters using the plurality of corrections, the adjustment resulting in at least one set of corrected phase shifter values.

Abstract: Aspects of the disclosure provide a method of adjusting a plurality of phase shifters of an OPA. The method may include identifying, by one or more processors, one or more first subsets of phase shifters of the plurality of phase shifters based on an orthogonal set of functions; performing, by the one or more processors, one or more first dithers on the one or more first subsets of phase shifters of the plurality of phase shifters using one or more first frequencies of a predetermined set of frequencies; determining, by the one or more processors, one or more first corrections based on a first power output of the OPA resulting from the one or more first dithers; and adjusting, by the one or more processors, the one or more first subsets using the one or more first corrections, the adjustment resulting in a first set of corrected phase shifter values.

Abstract: A monostatic, beaconless fiber transceiver for free-space optical links infers fine tracking information using receiver optoelectronics and an injected pointing dither (nutation). A MEMS steering mirror fine-points the beams and injects the nutation. While this may disturb fiber coupling and transmit beam pointing, link loss becomes negligible for sufficient SNR. The SNR for links without point-ahead correction is about 35 dB to keep dither loss below 0.1 dB and RMS spatial tracking noise below a tenth of the beam divergence. Since the pointing and tracking bandwidth is much smaller than the receiver communication bandwidth, this SNR is achievable with appropriate filtering. For point-ahead correction, a single-mode fiber transceiver can reach up to about 1 beamwidth of correction, while a few-mode fiber transceiver can reach up to about 1.75 beamwidths due to improved coupling sensitivity at higher point-ahead offsets.

Abstract: A monostatic, beaconless fiber transceiver for free-space optical links infers fine tracking information using receiver optoelectronics and an injected pointing dither (nutation). A MEMS steering mirror fine-points the beams and injects the nutation. While this may disturb fiber coupling and transmit beam pointing, link loss becomes negligible for sufficient SNR. The SNR for links without point-ahead correction is about 35 dB to keep dither loss below 0.1 dB and RMS spatial tracking noise below a tenth of the beam divergence. Since the pointing and tracking bandwidth is much smaller than the receiver communication bandwidth, this SNR is achievable with appropriate filtering. For point-ahead correction, a single-mode fiber transceiver can reach up to about 1 beamwidth of correction, while a few-mode fiber transceiver can reach up to about 1.75 beamwidths due to improved coupling sensitivity at higher point-ahead offsets.