Abstract: The disclosure provides a system for transmitting and receiving optical signals. The system includes a first mirror of a communication device, a first mirror actuator configured to control a pointing direction of the first mirror, a second mirror of the communication device, a second mirror actuator configured to control a pointing direction of the second mirror, and one or more processors. The one or more processors are configured to direct the second mirror actuator to move the second mirror to track a signal within a zone in an area of coverage of the communication device and meanwhile keep the first mirror stationary at a first angle. The one or more processors are also configured to direct the first mirror actuator to move the first mirror to a second angle in a direction of motion of the signal when the signal reaches an edge of the zone and meanwhile move the second mirror to a default angle.

Abstract: Aspects of the disclosure provide for a method of transmitting state information using free-space optical communication. The method includes using one or more processors of a first communication device to collect state information of the first communication device. A supervisor signal that carries the state information is transmitted from the first communication device along with a beacon beam in a first solid angle. The supervisor signal is a frequency different from the one or more frequencies of the beacon beam. When a communication link is established between the first communication device and a second communication device, a plurality of data packets is transmitted from the first communication device to the second communication device in a second solid angle smaller than the first solid angle. A subset of the plurality of data packets that do not carry client data carries the state information of the first communication device.

Abstract: Aspects of the disclosure provide for a method of aligning a tracking system of a communication device. The method includes receiving an optical beam at the communication device. A first beam portion is received at the tracking system, and a second beam portion is received at an optical fiber of the communication device. Using one or more processors, an first signal and an second signal is received from the tracking system. The one or more processors are also used to determine a phase difference related to the first signal and a second phase difference related to the second signal. An offset for the first signal and an offset for the second signal are determined based on the respective phase difference. The one or more processors then track the optical beam using the tracking system and the determined offsets.

Abstract: The disclosure provides a system for transmitting and receiving optical signals. The system includes a first mirror of a communication device, a first mirror actuator configured to control a pointing direction of the first mirror, a second mirror of the communication device, a second mirror actuator configured to control a pointing direction of the second mirror, and one or more processors. The one or more processors are configured to direct the second mirror actuator to move the second mirror to track a signal within a zone in an area of coverage of the communication device and meanwhile keep the first mirror stationary at a first angle. The one or more processors are also configured to direct the first mirror actuator to move the first mirror to a second angle in a direction of motion of the signal when the signal reaches an edge of the zone and meanwhile move the second mirror to a default angle.

Abstract: The disclosure provides for a method and a system for tracking an optical communication beam based on polarization modulation of the optical communication beam. The method includes polarizing, at a first communication device, an optical communication beam in a polarization pattern. The optical communication beam carries an optical signal. The polarization pattern encodes information by varying between a first polarization direction and at least one second polarization direction. The polarized optical communication beam is then transmitted from the first communication device to a second communication device. At the second communication device, the polarized optical communication beam is processed to extract the encoded information, and the encoded information is used at the second communication device to track the optical communication beam.

Abstract: Aspects of the disclosure provide for a method of transmitting state information using free-space optical communication. The method includes using one or more processors of a first communication device to collect state information of the first communication device. A supervisor signal that carries the state information is transmitted from the first communication device along with a beacon beam in a first solid angle. The supervisor signal is a frequency different from the one or more frequencies of the beacon beam. When a communication link is established between the first communication device and a second communication device, a plurality of data packets is transmitted from the first communication device to the second communication device in a second solid angle smaller than the first solid angle. A subset of the plurality of data packets that do not carry client data carries the state information of the first communication device.

Abstract: Aspects of the disclosure provide for a method of transmitting state information using free-space optical communication. The method includes using one or more processors of a first communication device to collect state information of the first communication device. A supervisor signal that carries the state information is transmitted from the first communication device along with a beacon beam in a first solid angle. The supervisor signal is a frequency different from the one or more frequencies of the beacon beam. When a communication link is established between the first communication device and a second communication device, a plurality of data packets is transmitted from the first communication device to the second communication device in a second solid angle smaller than the first solid angle. A subset of the plurality of data packets that do not carry client data carries the state information of the first communication device.

Abstract: Aspects of the disclosure provide for a method of aligning a tracking system of a communication device. The method includes receiving an optical beam at the communication device. A first beam portion is received at the tracking system, and a second beam portion is received at an optical fiber of the communication device. Using one or more processors, an first signal and an second signal is received from the tracking system. The one or more processors are also used to determine a phase difference related to the first signal and a second phase difference related to the second signal. An offset for the first signal and an offset for the second signal are determined based on the respective phase difference. The one or more processors then track the optical beam using the tracking system and the determined offsets.

Abstract: The disclosure provides for a method and a system for tracking an optical communication beam based on polarization modulation of the optical communication beam. The method includes polarizing, at a first communication device, an optical communication beam in a polarization pattern. The optical communication beam carries an optical signal. The polarization pattern encodes information by varying between a first polarization direction and at least one second polarization direction. The polarized optical communication beam is then transmitted from the first communication device to a second communication device. At the second communication device, the polarized optical communication beam is processed to extract the encoded information, and the encoded information is used at the second communication device to track the optical communication beam.

Abstract: Aspects of the disclosure provide for a method of transmitting state information using free-space optical communication. The method includes using one or more processors of a first communication device to collect state information of the first communication device. A supervisor signal that carries the state information is transmitted from the first communication device along with a beacon beam in a first solid angle. The supervisor signal is a frequency different from the one or more frequencies of the beacon beam. When a communication link is established between the first communication device and a second communication device, a plurality of data packets is transmitted from the first communication device to the second communication device in a second solid angle smaller than the first solid angle. A subset of the plurality of data packets that do not carry client data carries the state information of the first communication device.

Abstract: Aspects of the disclosure provide for a method of aligning a tracking system of a communication device. The method includes receiving an optical beam at the communication device. A first beam portion is received at the tracking system, and a second beam portion is received at an optical fiber of the communication device. Using one or more processors, an first signal and an second signal is received from the tracking system. The one or more processors are also used to determine a phase difference related to the first signal and a second phase difference related to the second signal. An offset for the first signal and an offset for the second signal are determined based on the respective phase difference. The one or more processors then track the optical beam using the tracking system and the determined offsets.

Abstract: The method includes receiving axis signals from a multi-axis position sensing detector, generating a reference signal by summing the axis signals, determining a mirror position of a mirror directing the optical beam based on the beam position error of each axis of the multi-axis position sensing detector, and actuating the mirror to move to the mirror position. Each axis signal is indicative of a beam position of an optical beam incident on the multi-axis position sensing detector, each axis signal corresponding to an axis of the multi-axis position sensing detector. For each axis of the multi-axis position sensing detector, the method includes converting a phase of an axis to have a 90 degree phase difference from a signal of the axis, generating an axis-phasor signal by summing the axis signals, and comparing the axis-phasor signal and the reference signal to determine a phase difference.

Abstract: Aspects of the disclosure provide for a method of transmitting state information using free-space optical communication. The method includes using one or more processors of a first communication device to collect state information of the first communication device. A supervisor signal that carries the state information is transmitted from the first communication device along with a beacon beam in a first solid angle. The supervisor signal is a frequency different from the one or more frequencies of the beacon beam. When a communication link is established between the first communication device and a second communication device, a plurality of data packets is transmitted from the first communication device to the second communication device in a second solid angle smaller than the first solid angle. A subset of the plurality of data packets that do not carry client data carries the state information of the first communication device.

Abstract: The method includes receiving axis signals from a multi-axis position sensing detector, generating a reference signal by summing the axis signals, determining a mirror position of a mirror directing the optical beam based on the beam position error of each axis of the multi-axis position sensing detector, and actuating the mirror to move to the mirror position. Each axis signal is indicative of a beam position of an optical beam incident on the multi-axis position sensing detector, each axis signal corresponding to an axis of the multi-axis position sensing detector. For each axis of the multi-axis position sensing detector, the method includes converting a phase of an axis to have a 90 degree phase difference from a signal of the axis, generating an axis-phasor signal by summing the axis signals, and comparing the axis-phasor signal and the reference signal to determine a phase difference.

Abstract: The method includes receiving axis signals from a multi-axis position sensing detector, generating a reference signal by summing the axis signals, determining a mirror position of a mirror directing the optical beam based on the beam position error of each axis of the multi-axis position sensing detector, and actuating the mirror to move to the mirror position. Each axis signal is indicative of a beam position of an optical beam incident on the multi-axis position sensing detector, each axis signal corresponding to an axis of the multi-axis position sensing detector. For each axis of the multi-axis position sensing detector, the method includes converting a phase of an axis to have a 90 degree phase difference from a signal of the axis, generating an axis-phasor signal by summing the axis signals, and comparing the axis-phasor signal and the reference signal to determine a phase difference.

Abstract: The method includes receiving axis signals from a multi-axis position sensing detector, generating a reference signal by summing the axis signals, determining a mirror position of a mirror directing the optical beam based on the beam position error of each axis of the multi-axis position sensing detector, and actuating the mirror to move to the mirror position. Each axis signal is indicative of a beam position of an optical beam incident on the multi-axis position sensing detector, each axis signal corresponding to an axis of the multi-axis position sensing detector. For each axis of the multi-axis position sensing detector, the method includes converting a phase of an axis to have a 90 degree phase difference from a signal of the axis, generating an axis-phasor signal by summing the axis signals, and comparing the axis-phasor signal and the reference signal to determine a phase difference.