Abstract: A free-space optical (FSO) retransmission device includes a memory bank partitioned into at least a source buffer indexed by segment identifications (IDs), an interface in communication with an optical terminal and an Ethernet network, and a programmable circuit configured to execute data process operations. The data process operations include receiving data from the Ethernet network, generating an FSO segment including the data received from the Ethernet network and a segment ID, generating and transmitting an outgoing FSO frame to the optical terminal, the outgoing FSO frame including an outgoing FSO segment, and storing the outgoing FSO segment in the source buffer until a corresponding acknowledgement is received in an inbound FSO frame from the optical terminal.

Abstract: A free-space optical (FSO) retransmission device includes a memory bank partitioned into at least a source buffer indexed by segment identifications (IDs), an interface in communication with an optical terminal and an Ethernet network, and a programmable circuit configured to execute data process operations. The data process operations include receiving data from the Ethernet network, generating an FSO segment including the data received from the Ethernet network and a segment ID, generating and transmitting an outgoing FSO frame to the optical terminal, the outgoing FSO frame including an outgoing FSO segment, and storing the outgoing FSO segment in the source buffer until a corresponding acknowledgement is received in an inbound FSO frame from the optical terminal.

Abstract: An optical circuit breaker includes a main optical transmission path including an optical coupler, a delay line and a protection device, and a parallel protection path configured to receive a tapped portion of a signal provided to the main optical transmission path and generate a reference signal based on the tapped portion. The protection device may be configured to be triggered to prevent an overpower condition from passing through the optical circuit breaker responsive to the reference signal exceeding a user selectable threshold. The delay line may be configured to have a longer delay than a time it takes for the protection device to be triggered via the parallel protection path.

Abstract: An optical communications beacon receiver including a camera for capturing a plurality of beacon images. The plurality of beacon images includes a beacon signal transmitted from a beacon transmitter. The beacon receiver also including processing circuitry configured for determining the state of the beacon signal for each of the plurality of beacon images based on the known pattern, at least one beacon image of the plurality of beacon images includes a beacon on state and at least one beacon image of the plurality of beacon images includes a beacon off state, comparing the at least one beacon image including the beacon on state to the at least one beacon image including the beacon off state, and determining a beacon location based on the comparison of the at least one beacon image including the beacon on state to the at least one beacon image including the beacon off state.

Abstract: An optical communications beacon receiver including a camera for capturing a plurality of beacon images. The plurality of beacon images includes a beacon signal transmitted from a beacon transmitter. The beacon receiver also including processing circuitry configured for determining the state of the beacon signal for each of the plurality of beacon images based on the known pattern, at least one beacon image of the plurality of beacon images includes a beacon on state and at least one beacon image of the plurality of beacon images includes a beacon off state, comparing the at least one beacon image including the beacon on state to the at least one beacon image including the beacon off state, and determining a beacon location based on the comparison of the at least one beacon image including the beacon on state to the at least one beacon image including the beacon off state.

Abstract: An optical circuit breaker includes a main optical transmission path including an optical coupler, a delay line and a protection device, and a parallel protection path configured to receive a tapped portion of a signal provided to the main optical transmission path and generate a reference signal based on the tapped portion. The protection device may be configured to be triggered to prevent an overpower condition from passing through the optical circuit breaker responsive to the reference signal exceeding a user selectable threshold. The delay line may be configured to have a longer delay than a time it takes for the protection device to be triggered via the parallel protection path.

Abstract: A universal optical receiver may include an optical channel monitor configured to acquire spectral data for an optical signal on at least one selected optical channel, a tunable local oscillator configured to be tuned to a center frequency of the optical signal on the at least one selected optical channel, a storage device configured to store data associated with the optical signal responsive to acquisition of the spectral data and tuning of the tunable local oscillator, and processing circuitry configured to execute an algorithm that employs a plurality of binary distinctions based on physical characteristics of the optical signal and employs at least one calculation of figure of merit associated with a series of parameter values of the optical signal to identify a format of the optical signal.

Abstract: To stabilize power to an optical multimode receiver a multimode variable optical attenuator is connected to the receiver with the attenuator's voltage being controlled using a feedback signal provided by an output detector, the signal being processed using a control algorithm based on proportional-integrate-differential theory.

Abstract: At least two single-mode optical fibers are fused together such that their cores are separated by only a few microns to serve as a capture element of an incoming beam of light in an optical terminal.

Abstract: Methods and systems to control a gain applied to a free-space optical (FSO) signal to reduce time-varying intensity fluctuations. An optical pre-amplifier may provide a first, relatively moderate gain with low noise factor (NF). A second optical amplifier may provide a second gain. Amplification may include doped fiber amplification (DFA), such as erbium-doped fiber amplification (EDFA) and/or Raman amplification. A variable optical attenuator (VOA) may be controllable with a relatively fast response time to reduce the time-varying intensity fluctuations. The VOA may effectively control an overall system gain. The gain of the first and/or second optical amplifier may also be controllable to reduce the time-varying intensity fluctuations. Optical intensities may be detected at one or more locations to support one or more feed-forward and/or feedback control loops. A clamp may be applied when an optical power reaches a threshold.

Abstract: A universal optical receiver may include an optical channel monitor configured to acquire spectral data for an optical signal on at least one selected optical channel, a tunable local oscillator configured to be tuned to a center frequency of the optical signal on the at least one selected optical channel, a storage device configured to store data associated with the optical signal responsive to acquisition of the spectral data and tuning of the tunable local oscillator, and processing circuitry configured to execute an algorithm that employs a plurality of binary distinctions based on physical characteristics of the optical signal and employs at least one calculation of figure of merit associated with a series of parameter values of the optical signal to identify a format of the optical signal.

Abstract: A customized bit error rate tester that characterizes data transmission through a free space optical channel that overcomes the limitations of commercial based bit error rate testers by providing visibility into packet based channel capacity by measuring bit-level statistics not dominated by fades. In this manner, fade characteristics can be measured and a relationship between fade time and data packet lengths can be developed. Further, analog outputs provide visual real-time data link statistics.

Abstract: Methods and systems to control a gain applied to a free-space optical (FSO) signal to reduce time-varying intensity fluctuations. An optical pre-amplifier may provide a first, relatively moderate gain with low noise factor (NF). A second optical amplifier may provide a second gain. Amplification may include doped fiber amplification (DFA), such as erbium-doped fiber amplification (EDFA) and/or Raman amplification. A variable optical attenuator (VOA) may be controllable with a relatively fast response time to reduce the time-varying intensity fluctuations. The VOA may effectively control an overall system gain. The gain of the first and/or second optical amplifier may also be controllable to reduce the time-varying intensity fluctuations. Optical intensities may be detected at one or more locations to support one or more feed-forward and/or feedback control loops. A clamp may be applied when an optical power reaches a threshold.

Abstract: A customized bit error rate tester that characterizes data transmission through a free space optical channel that overcomes the limitations of commercial based bit error rate testers by providing visibility into packet based channel capacity by measuring bit-level statistics not dominated by fades. In this manner, fade characteristics can be measured and a relationship between fade time and data packet lengths can be developed. Further, analog outputs provide visual real-time data link statistics.

Abstract: At least two single-mode optical fibers are fused together such that their cores are separated by only a few microns to serve as a capture element of an incoming beam of light in an optical terminal.

Abstract: To stabilize power to an optical multimode receiver a multimode variable optical attenuator is connected to the receiver with the attenuator's voltage being controlled using a feedback signal provided by an output detector, the signal being processed using a control algorithm based on proportional-integrate-differential theory.

Abstract: Hybrid methods and apparatus for transforming the state of polarization of an electromagnetic wave are provided. The method includes varying both the retardation and the angular rotation of at least one section of a polarization transformer.