Abstract: The optical tracking module includes an optical phased array (OPA), an analog drive, an integrated photodetector, and one or more processors. The OPA includes a plurality of array elements, and a plurality of phase shifters. The analog drive is configured to adjust the plurality of phase shifters. The integrated photodetector is configured to receive light from the OPA. The one or more processors is configured to extract signal information of an incoming beam via the OPA, and control an outgoing beam using the analog drive based on the signal information. The OPA, the analog drive, the integrated photodetector and the one or more processors are in an integrated circuit.

Abstract: An optical communication system includes an optical transmitter and one or more processors. The optical transmitter is configured to output an optical signal, and includes an average-power-limited optical amplifier, such as an erbium-doped fiber amplifier (EDFA). The one or more processors are configured to receive optical signal data related to a received power for a communication link from a remote communication system and determine that the optical signal data is likely to fall below a minimum received power within a time interval. In response to the determination, the one or more processors are configured to determine a duty cycle of the optical transmitter based on a minimum on-cycle length and a predicted EDFA output power and operate the optical transmitter using the determined duty cycle to transmit an on-cycle power that is no less than the minimum required receiver power for error-free operation of the communication link.

Abstract: The optical tracking module includes an optical phased array (OPA), an analog drive, an integrated photodetector, and one or more processors. The OPA includes a plurality of array elements, and a plurality of phase shifters. The analog drive is configured to adjust the plurality of phase shifters. The integrated photodetector is configured to receive light from the OPA. The one or more processors is configured to extract signal information of an incoming beam via the OPA, and control an outgoing beam using the analog drive based on the signal information. The OPA, the analog drive, the integrated photodetector and the one or more processors are in an integrated circuit.

Abstract: A system includes a transmitter configured to output an optical signal. The transmitter includes a seed laser, an optical array including a plurality of array elements, and a plurality of phase shifters in a multi-layer arrangement. The multi-layer arrangement includes a plurality of layers between the seed laser and the optical array, wherein a first layer of the plurality of layers transmits light to a second layer of the plurality of layers. The first layer has fewer phase shifters than the second layer. The multi-layer arrangement also includes a plurality of branches wherein each branch includes a phase shifter from each of the plurality of layers connected in series between the seed laser and one of the plurality of array elements. Each phase shifter is configured to shift the optical signal incrementally to amass a total phase shift for each of the plurality of array elements.

Abstract: The technology employs a state-based power control loop (PCL) architecture to maintain tracking and communication signal-to-noise ratios at suitable levels for optimal tracking performance and data throughput in a free-space optical communication system. Power for a link is adjustable to stay within a functional range of receiving sensors in order to provide continuous service to users. This avoids oversaturation and possible damage to the equipment. The approach can include decreasing or increasing the power to counteract a surge or drop while maintaining a near constant received power at a remote communication device. The system may receive power adjustment feedback from another communication terminal and perform state-based power control according to the received feedback. This can include re-initializing and reacquiring a link with the other communication terminal automatically after loss of power, without human intervention.

Abstract: A system includes a transmitter configured to output an optical signal. The transmitter includes a seed laser, an optical array including a plurality of array elements, and a plurality of phase shifters in a multi-layer arrangement. The multi-layer arrangement includes a plurality of layers between the seed laser and the optical array, wherein a first layer of the plurality of layers transmits light to a second layer of the plurality of layers. The first layer has fewer phase shifters than the second layer. The multi-layer arrangement also includes a plurality of branches wherein each branch includes a phase shifter from each of the plurality of layers connected in series between the seed laser and one of the plurality of array elements. Each phase shifter is configured to shift the optical signal incrementally to amass a total phase shift for each of the plurality of array elements.

Abstract: The technology relates to free-space optical communication systems that correct for errors in tracking and pointing accuracy to maintain connection integrity. Such systems can both proactively and reactively correct for errors in tracking performance and pointing accuracy of terminals within the system. An aspect includes receiving information indicative of at least one external disturbance associated with a communication device. A determination is made for a proactive estimation indicative of a first error associated with an effect of the at least one external disturbance at a current timestep. A determination is made for a reactive estimation indicative of a second error associated with the effect of the at least one external disturbance at a previous timestep. A final control signal is determined based on the proactive estimation and the reactive estimation. A controller is able to actuate an optical assembly of the communication device based on the determined final control signal.

Abstract: The disclosure provides for a method for reacquiring a communication link between a first communication device and a second communication device. The method includes using one or more processors of the first communication device to receive historical data related to the first communication device and an environment surrounding the first communication device. The one or more processors are then used to determine one or more trends in the historical data related to fading of the communication link. Based on the one or more trends, the one or more processors are used to determine a starting time and an initial search direction for a search for the communication link. The one or more processors then execute the search at the starting time from the initial search direction.

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 for reacquiring a communication link between a first communication device and a second communication device. The method includes using one or more processors of the first communication device to receive historical data related to the first communication device and an environment surrounding the first communication device. The one or more processors are then used to determine one or more trends in the historical data related to fading of the communication link. Based on the one or more trends, the one or more processors are used to determine a starting time and an initial search direction for a search for the communication link. The one or more processors then execute the search at the starting time from the initial search direction.

Abstract: The technology employs a state-based power control loop (PCL) architecture to maintain tracking and communication signal-to-noise ratios at suitable levels for optimal tracking performance and data throughput in a free-space optical communication system. Power for a link is adjustable to stay within a functional range of receiving sensors in order to provide continuous service to users. This avoids oversaturation and possible damage to the equipment. The approach can include decreasing or increasing the power to counteract a surge or drop while maintaining a near constant received power at a remote communication device. The system may receive power adjustment feedback from another communication terminal and perform state-based power control according to the received feedback. This can include re-initializing and reacquiring a link with the other communication terminal automatically after loss of power, without human intervention.

Abstract: An optical communication system includes an optical transmitter and one or more processors. The optical transmitter is configured to output an optical signal, and includes an average-power-limited optical amplifier, such as an erbium-doped fiber amplifier (EDFA). The one or more processors are configured to receive optical signal data related to a received power for a communication link from a remote communication system and determine that the optical signal data is likely to fall below a minimum received power within a time interval. In response to the determination, the one or more processors are configured to determine a duty cycle of the optical transmitter based on a minimum on-cycle length and a predicted EDFA output power and operate the optical transmitter using the determined duty cycle to transmit an on-cycle power that is no less than the minimum required receiver power for error-free operation of the communication link.

Abstract: An optical phased array (OPA) photonic integrated chip includes a plurality of array elements, a plurality of phase shifters, a plurality of combiners, and an edge coupler configured to couple to a single mode waveguide. The plurality of phase shifters includes a layer of phase shifters that has a phase shifter connected to each array element in the plurality of array elements. The plurality of combiners is configured to connect the plurality of phase shifters to the edge coupler. The plurality of combiners includes a first combiner that has a first output that is connected to a second combiner or the edge coupler, and a second output of the first combiner is connected to a photodetector. An in-phase light portion at the first combiner is output through the first output, and an out-of-phase light portion at the first combiner is output through the second output.

Abstract: A free-space optical communication system includes an optical phased array (OPA) photonic integrated chip, a transceiver photonic integrated chip, and one or more processors. The OPA chip includes a plurality of array elements and a plurality of phase shifters. The transceiver chip includes one or more transmitter components and one or more receiver components. The one or more processors are configured to transmit a first signal via the OPA chip and the transceiver chip, and receive a second signal via the OPA chip and the transceiver chip.

Abstract: The optical tracking module includes an optical phased array (OPA), an analog drive, an integrated photodetector, and one or more processors. The OPA includes a plurality of array elements, and a plurality of phase shifters. The analog drive is configured to adjust the plurality of phase shifters. The integrated photodetector is configured to receive light from the OPA. The one or more processors is configured to extract signal information of an incoming beam via the OPA, and control an outgoing beam using the analog drive based on the signal information. The OPA, the analog drive, the integrated photodetector and the one or more processors are in an integrated circuit.

Abstract: An optical communication system includes an optical transmitter and one or more processors. The optical transmitter is configured to output an optical signal, and includes an average-power-limited optical amplifier, such as an erbium-doped fiber amplifier (EDFA). The one or more processors are configured to receive optical signal data related to a received power for a communication link from a remote communication system and determine that the optical signal data is likely to fall below a minimum received power within a time interval. In response to the determination, the one or more processors are configured to determine a duty cycle of the optical transmitter based on a minimum on-cycle length and a predicted EDFA output power and operate the optical transmitter using the determined duty cycle to transmit an on-cycle power that is no less than the minimum required receiver power for error-free operation of the communication link.

Abstract: The technology employs a state-based power control loop (PCL) architecture to maintain tracking and communication signal-to-noise ratios at suitable levels for optimal tracking performance and data throughput in a free-space optical communication system. Power for a link is adjustable to stay within a functional range of receiving sensors in order to provide continuous service to users. This avoids oversaturation and possible damage to the equipment. The approach can include decreasing or increasing the power to counteract a surge or drop while maintaining a near constant received power at a remote communication device. The system may receive power adjustment feedback from another communication terminal and perform state-based power control according to the received feedback. This can include re-initializing and reacquiring a link with the other communication terminal automatically after loss of power, without human intervention.

Abstract: A system includes a transmitter configured to output an optical signal. The transmitter includes a seed laser, an optical array including a plurality of array elements, and a plurality of phase shifters in a multi-layer arrangement. The multi-layer arrangement includes a plurality of layers between the seed laser and the optical array, wherein a first layer of the plurality of layers transmits light to a second layer of the plurality of layers. The first layer has fewer phase shifters than the second layer. The multi-layer arrangement also includes a plurality of branches wherein each branch includes a phase shifter from each of the plurality of layers connected in series between the seed laser and one of the plurality of array elements. Each phase shifter is configured to shift the optical signal incrementally to amass a total phase shift for each of the plurality of array elements.

Abstract: The disclosure provides for a method for reacquiring a communication link between a first communication device and a second communication device. The method includes using one or more processors of the first communication device to receive historical data related to the first communication device and an environment surrounding the first communication device. The one or more processors are then used to determine one or more trends in the historical data related to fading of the communication link. Based on the one or more trends, the one or more processors are used to determine a starting time and an initial search direction for a search for the communication link. The one or more processors then execute the search at the starting time from the initial search direction.

Abstract: A free-space optical communication device includes an optical fiber bundle and one or more processors. The optical fiber bundle includes a central fiber connected to a first photodetector, and a plurality of surrounding fibers, each surrounding fiber connected to a corresponding second photodetector. The one or more processors are in communication with the first photodetector and each second photodetector. The one or more processors are also configured to receive a current or voltage generated at the first photodetector and each second photodetector and to determine a pointing accuracy of a beam received at the optical fiber bundle based on the current or voltage generated at the second photodetectors.