Abstract: Free space optical systems and methods of controlling the same for reducing signal fading of encoded optical beams transmitted in a communication channel are provided. Adjacent pairs of a plurality of apertures are separated by a distance being at least greater than the coherence width of the propagation medium of the communication channel. Due to averaging of the beams, variation in power at an optical receiver is reduced. By using an optical resonator in the optical receiver, the beams are converted into an intensity modulation on a non-interfering basis, thereby permitting recovery and decoding of the signal.

Abstract: Optical transmission device is provided in one of a plurality of nodes in an optical network. Different carrier frequencies are respectively allocated to the plurality of nodes. The optical transmission device includes: transmitter, splitter and receiver. The transmitter generates a first subcarrier optical signal with a first subcarrier established on a low-frequency side of a first carrier frequency and a second subcarrier optical signal with a second subcarrier established on a high-frequency side of the first carrier frequency. The splitter splits an optical signal including the first subcarrier optical signal and the second subcarrier optical signal. The output of the splitter is guided to first and second adjacent nodes. The receiver recovers data carried by the first subcarrier and data carried by the second subcarrier from received optical signal. A difference between carrier frequencies of adjacent nodes corresponds to a bandwidth of the subcarrier.

Abstract: An optical device includes a chip, a set of waveguides on the chip and configured to carry first optical signals modulated with data during a data transmission stage, and an alignment waveguide on the chip. The alignment waveguide is configured to receive a second optical signal during an alignment stage that aligns the set of waveguides with a collimator including a set of lenses. The alignment waveguide is configured to output the second optical signal from the chip. The second optical signal output from the chip is indicative of a quality of alignment between the set of waveguides and the collimator.

Abstract: There is provided an apparatus for fiber optic line continuity detection. The apparatus comprises an optical input connectable to a first optical fiber of a fiber optic line, an optical output connectable to a second optical fiber of the fiber optic line an optical interface unit configured to transmit and receive optical signals; and an optical switch having a first configuration and a second configuration. In the first configuration the optical switch is configured to pass optical signals received at the optical input to the optical interface unit and to pass optical signals received from the optical interface unit to the optical output. Whereas, in the second configuration the optical switch is configured to pass optical signals received at the optical input to the optical output.

Abstract: Techniques for tuning an optical communication system are disclosed. The system includes a first signal path for transmitting data, including an optical source, a first one or more variable optical attenuators (VOAs), a modulator, and a transmission fiber. The system further includes a second signal path for receiving data, including a receiver fiber and a second one more VOAs. The first one or more VOAs are tuned using the optical source in the first signal path for transmitting data, based on comparing a plurality of optical signal power values in the first path while a first tuning mode is enabled. The second one or more VOAs are tuned, using the optical source in the first signal path for transmitting data, based on comparing a plurality of optical signal power values in the second path while a second tuning mode is enabled.

Abstract: A quantum key generation system intended to mitigate the effect of the dead time of the photon detectors, the system including a photon generator, a photon pathway, a channel switch, and a photon detector unit. The photon pathway optically couples the photon generator and the channel switch. The channel switch is disposed between and optically coupled to the photon pathway and the photon detector unit. The photon detector unit includes a plurality of photon detectors and a plurality of detector unit sub-channels. Each detector unit sub-channel of the plurality of detector unit sub-channels optically couples the channel switch with an individual photon detector of the plurality of photon detectors. The channel switch is actuatable between a plurality of optical engagement positions. Further, each optical engagement position of the channel switch optically couples the photon pathway with a photon detector of the plurality of photon detectors.

Abstract: A visible light positioning receiver arrangement for obtaining spatial position information of the receiver arrangement from a plurality of luminaires (5), at least one of the luminaires including at least one associated modulated light source for transmitting a light signal providing positional information of one or more reference points associated with the luminaire, said receiver arrangement including: an imaging receiver for capturing an image of the luminaires and associated said reference point(s); and a non-imaging receiver (7) for estimating an angle of arrival (AOA) of light from each said modulated light source, and for decoding the reference point positional information therefrom; wherein said AOA information and reference point positional information from the non-imaging receiver is matched to the image captured by the imaging receiver to obtain said spatial position information.

Abstract: Systems and methods include receiving Open Shortest Path First (OSPF) packets from a plurality of OSPF areas; sending self-generated OSPF packets to the plurality of OSPF areas; and filtering of the received OSPF packets such that received Link State Advertisement (LSA) packets from an OSPF area (are not forwarded to other OSPF areas. In an embodiment, the systems and methods can be used for a scalable OSPF deployment for management of a network, such as an optical network.

Abstract: An optically powered switch. An example optically powered switch generally includes a light source configured to output an optical signal. The example optically powered switch generally includes a photodiode configured to convert the optical signal to an electrical signal. The example optically powered switch generally includes a bias and control circuit configured to power at least one radio frequency (RF) switch using the electrical signal.

Abstract: A system (100) for communicating a presence of a device via a light source (110) configured to emit light comprising an embedded code is disclosed. The system (100) comprises: a controller (102) comprising: a receiver (106) configured to receive a response signal from a first device (120), which response signal comprises an identifier of the first device (120), and which response signal is indicative of that the embedded code has been detected by the first device (120), and a processor (104) configured to correlate the embedded code with the identifier of the first device (120), such that the embedded code is representative of the identifier of the first device (120).

Abstract: A remote radio unit is for a base transceiver station. The remote radio unit includes: a noise generator configured to provide a RF noise signal having predefined statistical properties; a communication interface configured to transmit the RF noise signal as a stimulus signal over a radio-over-fiber uplink channel between the remote radio unit and a central unit of the base transceiver station for determining a pre-distortion of a target signal to be transmitted by the remote radio unit. The communication interface is further configured to receive the pre-distorted target signal over a ROF downlink channel between the remote radio unit and the central unit of the base transceiver station. The remote radio unit also has an antenna for transmitting the pre-distorted target signal received by the communication interface.

Abstract: An apparatus for signal modulation in a point-to-multipoint optical network is configured to modulate a single-wavelength carrier wave before distribution towards optical receivers of a first type adapted for intensity detection and a second type adapted for optical field detection. The apparatus includes a first module configured to modulate the carrier wave by varying the intensity of the carrier wave to represent data intended for the first type of receivers, and by controlling the phase and/or polarization of the carrier wave during selected periods. The apparatus includes a second module configured to modulate the carrier wave by varying the phase and/or polarization of the carrier wave to represent data intended for the second type of receivers, and by varying the intensity of the carrier wave during selected periods.

Abstract: An optical communication device including a GPS receiver receiving and outputting a GPS signal from a satellite; a main controller configured to generate and output synchronization data based on the GPS signal; and an optical transceiver configured to generate an optical signal by superposing input payload data and the synchronization data, and to output the optical signal, wherein a first communication channel corresponding to the payload data and a second communication channel corresponding to the synchronization data are different communication channels. According to embodiments, GPS information for synchronization together with payload data, which is information to be transmitted, may be efficiently transmitted between optical communication devices located in remote locations without separate wavelength allocation and connection of an optical cable, by using an auxiliary management and control channel (AMCC).

Abstract: A multi-speed integrated transceiver cabling system includes a cable coupled to a transceiver device that includes a transceiver processor and an optical waveguide coupling. A data receiving subsystem in the transceiver device couples the transceiver processor to the optical waveguide coupling, includes data receiving optical waveguides, and transmits first data received from the transceiver processor to the optical waveguide coupling over a number of the data receiving optical waveguides that depends on a first data transmission speed at which the first data was received.

Abstract: The present disclosure relates to a radio unit (420, 420A, 420B) adapted for cross-polar signal transfer (230), comprising an optical transmit interface (430, 430A, 430B) and an optical receive interface (440, 440A, 440B) which are arranged to transfer cross-polar signals for cross-polar interference cancellation, XPIC, to and from an external source, respectively. The optical transmit interface (430, 430A, 430B) and the optical receive interface (440, 440A, 440B) are arranged at equal distances (D) from a symmetry line (450) of the interfaces, and in a plane (451) perpendicular to the symmetry line (450). Upon rotation of the radio unit (420, 420A, 420B) about the symmetry line (450) by 180 degrees, the optical transmit interface after rotation aligns with the optical receive interface before rotation, and the optical receive interface after rotation aligns with the optical transmit interface before rotation.

Abstract: Apparatus for detecting pulse optical position modulated signals with high background noise by detection of quantum arrival rate at the detector are described. Pulse signals at the detection limit are characterized by the arrival of clusters of individual photons at an optical receiver. The receiver has embedded shot noise that interferes with the detection of the signal of interest. The apparatus distinguishes the signal of interest by a measurement of the rate of arrival of the photons of the signal of interest from the ambient shot noise rate of the receiver. The apparatus determines the optimal signal detection criteria and calculates the expected bit error rate of the decoded data.

Abstract: An optical signal monitor, including: a storage that holds a threshold value set for each of determination areas having a bandwidth set in accordance with an average grid of dummy light; a measurement section that sequentially measures an optical intensity of an inputted wavelength-multiplexed optical signal with respect to each of measurement areas obtained by dividing the determination area into areas with a bandwidth sufficiently smaller than a grid width of a monitoring-target optical signal composing the wavelength-multiplexed optical signal, and output measured values; and a section that determines that dummy light corresponding to the determination area needs introducing if each of measured values in the determination area is smaller than a threshold value, and, determines that dummy light corresponding to the determination area does not need introducing if at least one of the measured values in the determination area is equal to or larger than the threshold value.

Abstract: A directional free-space optical communication system includes a source device including a laser diode and an endpoint device including a photodiode. The endpoint device and the source device also include an adjustable optics subsystem that increases both angular and positional offset tolerance between the source device and the endpoint device.

Abstract: An optical wireless communication system comprising a transmitter apparatus that comprises: an illumination light source configured to output visible light for illumination purposes, and a controller configured to control operation of the illumination light source to produce modulation of the visible light to provide an optical wireless communication signal representing data; a further light source configured to output further light, wherein the controller is configured to control operation of the further light source to produce modulation of the further light to provide a further optical wireless communication signal representing substantially the same data, wherein the visible light and the further light have different wavelengths.

Abstract: An apparatus that adds and drops wavelength division multiplexed signal, the apparatus includes a memory and processor. The memory configured to store a first correspondence table indicating relationship with between an optical circuit type information and a first output level target value for a dropping circuit. The processor configured to determine an output level target value for the dropping circuit for each signal wavelength, based on the first correspondence table and optical circuit type information of each signal wavelength.