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.

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 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 communication device is provided that includes a first lens having a first surface and a second surface, a second lens having a third surface and a fourth surface, an optical fiber configured to output light including a plurality of ray bundles, and a photodetector located at the fourth surface of the second lens. The first lens is configured to cause the light output from the optical fiber to form an image at an image plane located at the third surface of the second lens. The second lens is configured to cause subsets of the ray bundles received at the third surface of the second lens to intersect or overlap at the photodetector in a smaller cross-sectional area than at the third surface of the second lens.

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: 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 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: 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 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: An optical communication device is provided that includes a first lens having a first surface and a second surface, a second lens having a third surface and a fourth surface, an optical fiber configured to output light including a plurality of ray bundles, and a photodetector located at the fourth surface of the second lens. The first lens is configured to cause the light output from the optical fiber to form an image at an image plane located at the third surface of the second lens. The second lens is configured to cause subsets of the ray bundles received at the third surface of the second lens to intersect or overlap at the photodetector in a smaller cross-sectional area than at the third surface of the second lens.

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: 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 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: An optical communication terminal is configured to operate in two different complementary modes of full duplex communication. In one mode, the terminal transmits light having a first wavelength and receives light having a second wavelength along a common free space optical path. In the other mode, the terminal transmits light having the second wavelength and receives light having the first wavelength. The terminal includes a steering mirror that directs light to and from a dichroic element that creates different optical paths depending on wavelength, and also includes spatially separated emitters and detectors for the two wavelengths. A first complementary emitter/detector pair is used in one mode, and a second pair is used for the other mode. The system also includes at least two ferrules. Each ferrule operates with a single emitter/detector pair. The ferrules are designed to operate interchangeably with either emitter/detector pair.

Abstract: The disclosure provides for an optical communication device that includes a photodetector, an optical fiber, a first lens, and a second lens. The optical fiber may be configured to relay light. The first lens may include a first surface and a second surface and has an image plane. The first lens may be configured to receive the light output from the optical fiber, where the received light has a first cross-sectional area at the first surface. The second lens may include a third surface positioned at the image plane of the first lens and a fourth surface positioned adjacent to the photodetector. The second lens may be configured to receive the light output from the first lens and to output light having a second cross-sectional area at the fourth surface that is smaller than the first cross-sectional area.

Abstract: An optical communication terminal is configured to operate in two different complementary modes of full duplex communication. In one mode, the terminal transmits light having a first wavelength and receives light having a second wavelength along a common free space optical path. In the other mode, the terminal transmits light having the second wavelength and receives light having the first wavelength. The terminal includes a steering mirror that directs light to and from a dichroic element that creates different optical paths depending on wavelength, and also includes spatially separated emitters and detectors for the two wavelengths. A first complementary emitter/detector pair is used in one mode, and a second pair is used for the other mode. The system also includes at least two ferrules. Each ferrule operates with a single emitter/detector pair. The ferrules are designed to operate interchangeably with either emitter/detector pair.

Abstract: An optical communication terminal is configured to operate in two different complementary modes of full duplex communication. In one mode, the terminal transmits light having a first wavelength and receives light having a second wavelength along a common free space optical path. In the other mode, the terminal transmits light having the second wavelength and receives light having the first wavelength. The terminal includes a steering mirror that directs light to and from a dichroic element that creates different optical paths depending on wavelength, and also includes spatially separated emitters and detectors for the two wavelengths. A first complementary emitter/detector pair is used in one mode, and a second pair is used for the other mode. The system also includes at least two ferrules. Each ferrule operates with a single emitter/detector pair. The ferrules are designed to operate interchangeably with either emitter/detector pair.

Abstract: An example beam splitting apparatus is assembled from multiple prisms that are assembled together along respective mating surfaces to form a single monolithic optical device. The beam splitting apparatus includes optical features, such as dichroic and reflective surfaces, that define optical paths for light that enters the beam splitting apparatus. The optical features allow photons in the light to be directed along different optical paths based on their wavelengths. The optical features in the beam splitting apparatus are provided by coatings, films, and/or surface treatments applied to any of the faces of the prisms. In particular, coatings, films, and/or surface treatments are applied to the mating surfaces of the prisms so that the optical features are internal to the assembled monolithic optical device. The beam splitting apparatus may be implemented in a communication terminal that exchanges data modulated light according to frequency-division duplex communications.

Abstract: An optical communication terminal is configured to operate in two different complementary modes of full duplex communication. In one mode, the terminal transmits light having a first wavelength and receives light having a second wavelength along a common free space optical path. In the other mode, the terminal transmits light having the second wavelength and receives light having the first wavelength. The terminal includes a steering mirror that directs light to and from a dichroic element that creates different optical paths depending on wavelength, and also includes spatially separated emitters and detectors for the two wavelengths. A first complementary emitter/detector pair is used in one mode, and a second pair is used for the other mode. The system also includes at least two ferrules. Each ferrule operates with a single emitter/detector pair. The ferrules are designed to operate interchangeably with either emitter/detector pair.