Abstract: An embodiment of the invention includes a tunable optical dispersion compensator (TODC) comprising a first beam displacer on an optical path, wherein the first beam displacer separates an optical signal into a first beam and a second beam, and one or more polarizing beam splitters on the optical path, wherein the one or more polarizing beam splitters keep the first beam and the second beam on the optical path. The TODC also comprises one or more etalons on the optical path, wherein the one or more etalons are tunable to introduce a group delay in the first beam and the second beam, and a reflecting mirror on the optical path, wherein the reflecting mirror returns the optical signal back along the optical path. The TODC further comprises a second beam displacer, wherein the second beam displacer combines the first beam and the second beam into an output optical signal.

Abstract: System (100) and methods (1100) for improving packet loss due to fast optical power fades in an FSO communication link (136). The methods involve: obtaining Channel Fade Statistics (“CFSs”) for the FSO communication link; and analyzing CFSs to determine if Redundant Packet Transmission (“RPT”) is required to mitigate fast optical power fading. If RPT is required, then first operations are performed at a data link layer (408) of a protocol stack (400) to generate first packets (600). Each packet has a sequence number (602) disposed between a data link layer header (502) and a network layer header (504). If RPT is not required, then second operations are performed at the data link layer to generate a second packet absent of the sequence number or alternatively having a sequence number equal to zero. Thereafter, the packet(s) is transmitted over the FSO communication link one or more times.

Abstract: A method and apparatus for establishing a terahertz link using a multi-element lens array that comprises a liquid lens are disclosed. For example, the method receives detected terahertz signals from one or more detectors, where a liquid lens is deployed with each of the one or more detectors. The method determines, for each of the detected signals, if the detected signal is out of focus, and applies a corrective voltage to each liquid lens that corresponds to a detected terahertz signal that is out of focus, wherein the corrective voltage adjusts a focus of the detected signal. The method measures a signal-to-noise ratio of the detected signals, and establishing a terahertz link via at least one of the detected terahertz signals with a highest signal-to-noise ratio.

Abstract: The invention provides power smart in-door optical wireless link that provides lossless beam propagation between Transmitter (T) and Receiver (R) for changing link distances including in conditions of transmit and receive beam spoiling due to environmental effects. Each T/R unit uses a combination of fixed and variable focal length optics (called inverse adaptive optics) to smartly adjust the transmit beam laser beam propagation parameters of minimum beam waist size and its location to produce the optimal zero propagation loss coupling condition at the Receiver for the specific link distance.

Abstract: A free space communications apparatus includes a first receiving element configured to receive a communication signal and an ambient noise signal and to generate a first current as a function of any and all received signals, a second receiving element electrically coupled with the first receiving element to receive the ambient noise signal and to generate a second current as a function of any and all received signals, and an output signal produced as a function of the communication signal received by the first receiving element. The first and second receiving elements are electrically connected in a circuit that cancels at least a portion of the first current as a function of the second current to produce the output signal.

Abstract: A lighting system includes light fixtures not in communications with and not synchronized with one another, and one or more light sensors. Each light fixture separately emits data encoded visible light including light fixture information encoded therein in a manner that avoids visually perceptible flicker and enables light fixture information emitted by one light fixture to be distinguished from light fixture information emitted by other light fixtures. The light fixture information is encoded into data encoded visible light such that a difference between different levels of the data encoded visible light is indicative of an illumination capability of the light fixture and such that visually perceptible flicker is avoided. Each light sensor separately receives portions of data encoded light visible light emitted by multiple light fixtures and separately determines the identity of and the maximum and present illumination contributions for each light fixture.

Abstract: A VLC (Visible Light Communication) modulation system and method thereof, which includes a visible light generating device and a visible light receiving device. The visible light generating device includes a visible light emitting module and an arbitrary waveform generator. The arbitrary waveform generator further includes a first finite impulse response filtering unit, a pre-distortion amount control unit, and a second finite impulse response filtering unit.

Abstract: A method and apparatus for establishing a terahertz link using a multi-element lens array that comprises a liquid lens are disclosed. For example, the method receives detected terahertz signals from one or more detectors, where a liquid lens is deployed with each of the one or more detectors. The method determines, for each of the detected signals, if the detected signal is out of focus, and applies a corrective voltage to each liquid lens that corresponds to a detected terahertz signal that is out of focus, wherein the corrective voltage adjusts a focus of the detected signal. The method measures a signal-to-noise ratio of the detected signals, and establishing a terahertz link via at least one of the detected terahertz signals with a highest signal-to-noise ratio.

Abstract: A method and apparatus for clearing an optical channel for transmitting data through free space between a first and second location includes a light beam, wherein the light beam has a spatially and/or time-dependent modulated intensity profile, and is substantially collimated so that the intensity profile is conserved over a specified distance of operation. The light beam includes a cross-sectional profile having regions of low and high intensity, portions of which are provided for the transmission of an optical data signal. A light source wavelength and intensity are selected for types of obscurant particles having optical properties whereby the radiation pressure acts on the particles, and the particles may then be either attracted into or repelled from portions of the spatially modulated optical beam, leaving certain portions of the optical channel beam absent of obscurant particles, thereby enabling transmission of optical data through the cleared optical channel with low attenuation.

Abstract: Disclosed herein are a visible light communication method and apparatus. The visible light communication method includes determining whether a current location is the start of a symbol of a transmission signal, setting a sample index, a signal accumulated value for an accumulation region of a front half portion of the symbol, and a signal accumulated value for an accumulation region of a rear half portion of the symbol, determining whether the sample index belongs to an accumulation region of the front or rear half portion of the symbol, and accumulating samples of the transmission signal in accordance with the location to which the sample index belongs, determining whether a current location corresponds to the end of the symbol, and outputting a Variable Pulse Position Modulation (VPPM) communication signal corresponding to the transmission signal.

Abstract: Embodiments relate to methods, devices, and computer-implemented methods for receiving a modulated signal transmitted from at least one signal emitter. The method can include receiving at least one image that comprises image data representing the modulated signal received as radiation emitted from the at least one signal emitter, wherein the radiation represented in the image data comprises at least one period of the modulated signal and wherein the at least one image was captured by a camera of a computing device while a field of view of the camera was moving relative to the at least one signal emitter; analyzing, by at least one processor, the at least one image; extracting, based on the analyzing, the image data representing the radiation; and determining, from the image data that was extracted, the modulated signal transmitted by the at least one signal emitter.

Abstract: The invention relates to a method and system for free-field optical transmission by means of laser signals, including setting a rate for encoding information that is useful for transmission on the basis of variations in a signal receiving characteristic belonging to a single communication session. The encoding rate is preferably dynamically adjusted during the communication session. An optimized compromise is thereby created between a useful rate that is high and a post-decoding bit error rate that is low. The method and the related system enable atmospheric conditions that can disrupt laser signal transmission to be taken into account in real time when said laser signals pass through part of the earth's atmosphere.

Abstract: Proposed is a light module (110) comprising at least two primary light sources (111,112,113) capable of emitting a primary color light. This allows the light module to emit light having intensity (Y) and color coordinates (x,y) through additive color mixing of the constituent primary colors. The light module further comprises an modulator (115) capable of modulating the primary light sources enabling embedment of data in the light emitted. The modulator (115) is arranged to modulate the color coordinates of the light emitted for embedding the data. This is especially advantageous as the sensitivity of the human eye to changes in color is lower than to changes in intensity. The invention thus advantageously allows embedding the data into the light emitted from the light modules (110) of an illumination system (100) without reducing the performance of its primary function as an aid to human vision.

Abstract: High power, high speed VCSEL arrays are employed in unique configurations of arrays and sub-arrays. Placement of a VCSEL array behind a lens allows spatial separation and directivity. Diffusion may be employed to increase alignment tolerance. Intensity modulation may be performed by operating groups of VCSEL emitters at maximum bias. Optical communications networks with high bandwidth may employ angular, spatial, and/or wavelength multiplexing. A variety of network topologies and bandwidths suitable for the data center may be implemented. Eye safe networks may employ VCSEL emitters may be paired with optical elements to reduce optical power density to eye safe levels.

Abstract: Systems and methods for visible light communication are disclosed. In part, illumination devices and related systems and methods are disclosed that can be used for general illumination, lighting control systems, or other applications. The illumination devices synchronize preferentially to the AC mains to produce time division multiplexed channels in which control information can be communicated optically by the same light source that is producing illumination. Such illumination devices preferentially comprise LEDs for producing illumination, transmitting data, detecting ambient light, and receiving data, however, other light sources and detectors can be used. The physical layer can be used with a variety of protocols, such as ZigBee, from the Media ACcess (MAC) layer and higher.

Abstract: Remote control signal detection systems and methods are operable to compensate detected infrared energy to identify an infrared energy communication signal emitted by a remote control. An exemplary embodiment detects first infrared energy, wherein the infrared energy communication signal is absent in the first infrared energy; determines compensation based on the first infrared energy; detects second infrared energy, wherein the infrared energy communication signal is present in the second infrared energy; and compensates the second infrared energy based on the determined compensation.

Abstract: Provided is an apparatus and method for transmitting and receiving data in a visible light communication system, the apparatus including a visible light communication (VLC) transceiver for converting a visible light signal received from a counterpart into an electrical signal and outputting the electrical signal, by using a light receiving device during a reception operation, and converting an electrical signal containing information into a visible light signal and transmitting the visible light signal to the counterpart, by using a light emitting device during a transmission operation, a VLC controller comprising a visible frame engine (VFE) for generating a visible frame and outputting the visible frame to the VLC transceiver, in which the VFE generates the visible frame for transmission to a counterpart during non-transmission of respective frames for communication at a sender and a receiver in order to provide visibility to a communication link, and a host controller for controlling the VLC controller and

Abstract: A method and apparatus are provided for attenuating an optical beam. The method includes selecting a level of attenuation to be applied to the optical beam. A pattern of on-state and off-state pixels in a two dimensional spatial light modulator (SLM) is selected such that the pattern will modulate the optical beam to provide the selected level of attenuation. Finally, the optical beam is directed onto the SLM while tile pixels are arranged in the selected pattern. The pattern is periodic along a first axis and symmetric along a second axis along which an intensity distribution of die optical beam extends.

Abstract: Methods, systems and other embodiments associated with a laser communication system using a single wavelength are presented. A first data is modulated onto an RF carrier to produce a modulated RF carrier. A laser is intensity modulated using with the modulated RF carrier. The intensity modulated laser beam is transmitted from an interrogator to a modulating retro-reflector (MRR) terminal. A portion of the laser beam is received at a receiver at the MRR terminal. Another portion of the laser is modulated at the MRR terminal with a second data to produce a re-modulated laser beam. The re-modulated laser beam is reflected back to the interrogator.

Abstract: A method and apparatus for establishing a terahertz link using a multi-element lens array that comprises a liquid lens are disclosed. For example, the method receives detected terahertz signals from one or more detectors, where a liquid lens is deployed with each of the one or more detectors. The method determines, for each of the detected signals, if the detected signal is out of focus, and applies a corrective voltage to each liquid lens that corresponds to a detected terahertz signal that is out of focus, wherein the corrective voltage adjusts a focus of the detected signal. The method measures a signal-to-noise ratio of the detected signals, and establishing a terahertz link via at least one of the detected terahertz signals with a highest signal-to-noise ratio.

Abstract: In a method for transmission of digital data in an optical free-space transmission system in which a binary code sequence produced from the digital data is used to transmit amplitude-modulated light waves across an optical free space between a transmitter and a receiver, according to a first aspect, the binary code sequence is produced such that a modulation frequency of the light waves determined by the binary code sequence has a value of 70 Hertz. According to a second aspect, ‘t’ light waves are modulated with the binary code sequence and binary data are transmitted in blocks during a first time period, and non-modulated light waves are emitted during second time periods, wherein the light intensities of the time periods are selected so that the quantities of light transmitted in two periods correspond to predetermined quantities of light.

Abstract: An optical transmission system having an optical source, an optical dispersion compensation filter optically connected to the optical source, and a control system. The optical source generates a modulated optical signal having an optical spectrum and a value of dispersion robustness. The optical dispersion compensation filter has at least two cascaded optical resonators and a periodic transfer function rigidly translatable in the frequency spectrum to obtain translation in frequency of the transfer function without a substantial change in shape, and characterized by a free spectral range. The control system acts on the optical dispersion compensation filter in order to rigidly translate the transfer function along the frequency spectrum in first and second positions in the frequency spectrum. The translation of the transfer function between the first and the second positions is smaller than the free spectral range.

Abstract: A method for generating a visible signal for a data transmission frame in a visible-light communication system includes: receiving specific data constituted by a plurality of frames from a sender; checking and converting a received signal strength indication (RSSI) signal measured from the sender; whenever each frame of the specific data is consecutively received, checking the converted RSSI, determining a level of a visible signal for distinctively displaying a state of a corresponding communication channel, and transmitting the level of the visible signal to the sender; and when reception of the specific data has finished, transmitting a corresponding response message to the sender, according to whether the specific data has been successfully received.

Abstract: An optical data transmission apparatus is provided, in which a first communication unit 101 and a second communication unit 102 arranged to freely move relatively to each other each include an optical signal transmission unit having a laser diode 120 for emitting single-mode light, a multi-mode optical fiber 111 for guiding a single-mode optical signal output from the laser diode 120 , converting the single-mode optical signal into a multi-mode optical signal, and outputting the multi-mode optical signal, an optical lens 112 for forming the optical signal output from the multi-mode optical fiber 111 into parallel light, and a first polarization element for passing the optical signal polarized in a predetermined direction out of optical signals output from the optical lens 112.

Abstract: A method for optically transmitting data between a transmitter and a receiver is provided, wherein a color coding method based on a plurality of elementary colors is provided for encoding and transmitting the data, wherein each elementary color is transmitted by a transmitter-side optical radiation source and is received on the receiver side by an optical radiation receiver. The method includes transmitting a training request message comprising calibration information formed on the transmitter side; forming a channel properties matrix by the receiver from the calibration information and storing the channel properties matrix in the receiver; calculating at least one compensation information on the basis of a reference channel properties matrix stored in the receiver and the reference channel properties matrix; and transmitting the compensation information from the receiver to the transmitter.

Abstract: An optical interconnect system includes components such as circuit boards, server blades, or a backplane with respective light pipes for an optical signal. The light pipe in a component transmitting the optical signal receives a collimated beam and directs the collimated beam for transmission. The light pipe in a receiving component is nominally aligned with the light pipe pf the transmitting component and separated from the first light pipe by free space. The light pipe on the receiving side is larger than the light pipe on the transmitting side and can therefore accommodate an expected alignment error.

Abstract: An LED light unit is provided with terminal pins at each end for fitting the light unit in place of a fluorescent tube of a fluorescent lighting fixture connected to a power source. The light unit has a circuit board with a plurality of diodes configured to provide at least one string of visible light producing LEDs and at least one string of zener diodes. The strings are driven by drive means whereby a constant input operating voltage to the light unit is provided when the light unit is used with a ballast and the power derived is dissipated in any one or more of the strings.

Abstract: An optical transmission system including an optical transmission path for transmitting WDM signals multiplexed different wavelength optical signals, the WDM signals including different bit rate optical signals or different modulation format optical signals; a repeater arranged in the optical transmission path, the repeater including a chromatic dispersion compensation unit for compensating chromatic dispersion compensation for the WDM signals; and a network management system including processes of determining a dispersion compensation ratio indicating the ratio with respect to the dispersion compensation amount at which the residual dispersion of the WDM signals are zero after transmission via the optical transmission path, on the bases of the mixture ratio of different optical signals included in the WDM signals, and variably setting the dispersion compensation amount for the in-line repeater according to the dispersion compensation ratio.

Abstract: A system and method for facilitating infrared (IR) communications from a first device, such as a set top box, to a second device, such as a remote control, in the presence of an IR noise generating device, such as a plasma television, by using at least one of the first device and the second device to actively reduce a level of IR noise being generated by the IR noise generating device during an IR transmission from the first device to the second device.

Abstract: A light emitting device, a light receiving device and a data transmission system and a data transmission method using the same are provided. The data transmission system includes the light emitting device and the light receiving device. The light emitting device includes a light emitting unit and a control circuit, and the light receiving device includes an image capture unit, a recognition unit and a decoding unit. The control circuit controls the light emitting unit to sequentially display a plurality of pattern images in a plurality of frame times to form a spatiotemporal pattern image according to setting data corresponding to a temporal domain and a spatial domain. The image capture unit captures the spatiotemporal pattern image. The recognition unit recognizes the spatiotemporal pattern image to output recognized data. The decoding unit decodes the recognized data to output decoded data.

Abstract: A free-space optical communications network for allowing a plurality of geographically-distributed users to communicate may include free-space multi-channel relay converters for tracking a plurality of users, and a connection system in communication with each of the plurality of multi-channel relay converters. The connection system may include an internal alignment reference and steering mirrors. Each free-space multi-channel relay converter may be adapted to align with the internal alignment reference. The connection system may be adapted to align the plurality of free-space multi-channel relay converters with one another to allow the plurality of geographically-distributed users to communicate.

Abstract: A method and system are provided for aligning the optic port of a device having a Free Space Optics (FSO) connector. In a link device with an FSO connector, a controller determines that an optic port alignment procedure is required. A lens is set to an initial wide beam dispersion mode, and a mirror is set to an initial position angle. Note: the lens and mirror may be the FSO connector receive path or transmit path. An optical signal is communicated at a first low baud rate, and the first baud rate communications are optimized by iteratively adjusting the mirror and narrowing the lens focus. Then, an optical signal is communicated at a second baud rate, faster than the first baud rate, and the second baud rate communications are optimized by iteratively adjusting the mirror and narrowing the lens focus.

Abstract: A wayfinding device is provided for giving directions to a desired destination within a building having a plurality of wayfinding beacons configured to transmit data using an ultrasound signal. The ultrasound signal can include a plurality of bursts, wherein a sequence of predefined time intervals between consecutive bursts within the plurality of bursts uniquely identifies each wayfinding beacon. The wayfinding device is separate from the wayfinding beacons and includes a wayfinding beacon recognition component configured to identify a wayfinding beacon when the device receives the data through the ultrasound signal from a wayfinding beacon. The device is further programmed to provide directions to a user of the device in a direction toward the desired destination in response to identifying a wayfinding beacon.

Abstract: A method and apparatus for clearing an optical channel for transmitting data through free space between a first and second location includes a light beam, wherein the light beam has a spatially and/or time-dependent modulated intensity profile, and is substantially collimated so that the intensity profile is conserved over a specified distance of operation. The light beam includes a cross-sectional profile having regions of low and high intensity, portions of which are provided for the transmission of an optical data signal. A light source wavelength and intensity are selected for types of obscurant particles having optical properties whereby the radiation pressure acts on the particles, and the particles may then be either attracted into or repelled from portions of the spatially modulated optical beam, leaving certain portions of the optical channel beam absent of obscurant particles, thereby enabling transmission of optical data through the cleared optical channel with low attenuation.

Abstract: An approach is provided that uses diversity to compensate fading of free-space optical (FSO) signals propagating through an environment characterized by atmospheric scintillation. One embodiment involves collecting at least one FSO beam, demultiplexing the beam by wavelength into at least two sub-beams, detecting each sub-beam to produce an electrical output therefrom, and recovering a signal using complementary information from at least two of the electrical outputs. Another embodiment involves collecting the FSO beam onto an array of spatially separated sub-apertures, detecting the light entering each sub-aperture to produce an electrical output therefrom, and recovering a signal using complementary information from at least two of the electrical outputs. This second embodiment enables both electronic adaptive processing to coherently integrate across the sub-apertures and in the case of multiple transmit apertures a free space optical Multiple Input Multiple Output (MIMO) system.

Abstract: A data signal to be transmitted is supplied to a modulator of a transmitter, and the modulator modulates the output of a blue light-excited white LED and outputs blue LED light and phosphor light. The modulated blue light enters to a photo-electric converter through an LED light transmission color filter. The modulated phosphor light on the other hand enters to another photo-electric converter through a phosphor light transmission color filter. The photo-electric converters convert incident light to electric signals. The converted signals are amplified by amplifiers. Then, equalizers emphasize the harmonic component therein according to the response characteristic of the blue light and the response characteristic of the phosphor light for reduction of the dullness of waveforms.

Abstract: According to an aspect of an embodiment, an apparatus comprises: a correction level calculating unit that calculates a correction level, which is the input light level necessary to meet an optical signal-to-noise ratio at the maximum level of an optical noise signal; a loss-of-light detection threshold-value setting unit that compares the correction level with an initial threshold value to set a loss-of-light detection threshold value used in detection of any loss of light on the basis of the comparison result; and a loss-of-light detecting unit that compares the level of an input optical signal with the loss-of-light detection threshold value to determine that any loss of light is caused if the level of the input optical signal is lower than the loss-of-light detection threshold value.

Abstract: An optoelectronic sensor includes at least one light transmitter for the transmission of light signals into a monitored zone, at least one light receiver for the reception of light signals transmitted from the light transmitter and a control device for the generation and/or influencing of the light signals and for the generation of an object detection signal in the case of the presence of an object in the monitored region in dependence on the output signals of the light receiver. In this connection, the light signals transmitted into the monitored zone by the light transmitter are each generated by an output signal modulated in accordance with the spread spectrum method using a random pseudo-noise code.

Abstract: A fiber laser arrangement having a high beaming power includes a plurality of continuously operating coherent individual fiber lasers. Pumping energy generated by a common master oscillator operated in the longitudinal mode is distributed to the fiber lasers by way of a fiber splitter, in a branched manner. An integrated electro-optical phase shifter is assigned to each individual fiber laser, and can be controlled by an electronic control system. By appropriate displacements of the optical phases in individual phases of the fiber laser arrangement atmospheric turbulence effects on the propagation path of the laser radiation to a target are compensated in order to obtain an optimal focusing of the entire laser radiation onto the remote target.

Abstract: Free space optical communication methods and systems, according to various aspects are described. The methods and systems are characterized by transmission of data through free space with a digitized optical signal acquired using wavelength modulation, and by discrimination between bit states in the digitized optical signal using a spectroscopic absorption feature of a chemical substance.

Abstract: An embodiment of the invention includes a tunable optical dispersion compensator (TODC) comprising a first beam displacer on an optical path, wherein the first beam displacer separates an optical signal into a first beam and a second beam, and one or more polarizing beam splitters on the optical path, wherein the one or more polarizing beam splitters keep the first beam and the second beam on the optical path. The TODC also comprises one or more etalons on the optical path, wherein the one or more etalons are tunable to introduce a group delay in the first beam and the second beam, and a reflecting mirror on the optical path, wherein the reflecting mirror returns the optical signal back along the optical path. The TODC further comprises a second beam displacer, wherein the second beam displacer combines the first beam and the second beam into an output optical signal.

Abstract: Embodiments include apparatus, methods, and system including an apparatus comprising a photo receiver operable to detect a stream of light pulses transmitted from a photo transmitter paired with the photo receiver, wherein a frequency of the stream of light pulses has a harmonic relationship with a frequency of at least one other stream of light pulses transmitted by a photo transmitter not paired to the photo receiver, wherein the stream of light pulses from the transmitter paired with the photo receiver is detectable by the photo receiver even when the photo receiver is receiving one or more light pulses from the at least one other stream of light pulses.

Abstract: An electronic system includes a first circuit board having a first optical element and a second circuit board having a second optical element positioned to electronically communicate with the first optical element over free space. The system also includes a cold plate having openings positioned to enable the optical communications over free space is positioned between the first circuit board and the second circuit board. The system further includes a condenser and a fluid conduit containing a cooling fluid configured to absorb heat through the cold plate and to convey the heat to the condenser, where the fluid conduit connects the cold plate and the condenser.

Abstract: In one embodiment a communications system includes an RF receiver that receives a desired signal and the interference signal, a first phase modulator that receives the desired signal and the interference signal from the RF receiver and generates a resulting optical signal, a second phase modulator that generates a modulated optical signal relative to an inverse interference signal and transmits the modulated optical signal to the first phase modulator, and a detector that receives the resulting optical signal from the first phase modulator and detects the desired signal, wherein the resulting optical signal comprises a modulated optical signal generated by the first phase modulator relative to the desired signal and the interference signal received from the RF receiver and relative to the modulated optical signal received from the second phase modulator.

Abstract: A method and system for visible light communication (VLC) for use in a dimmable lighting environment is provided. The method includes transmitting data using light from at least one light source, a brightness of the light reduced below a maximum level. The method also includes compensating or accommodating for the reduced brightness of the light at a VLC circuitry to maintain communication. The method further includes transmitting data to at least one VLC receiver using the light from the at least one light source.

Abstract: An infrared light emitting and receiving system (10) includes an infrared light emitting device (100), and an infrared light receiving device (200). The infrared light emitting device including a heat sink (102), at least a heat pipe (104), a metallic plate (106), and at least an infrared light source (108) in thermal connections with one other in that order. The infrared light receiving device receives infrared light beams (300) emitted from the infrared light emitting device, the infrared light receiving device comprising a lens barrel (202), at least one lens (204) received in the lens barrel, an infrared passband filter (220) formed on the at least one lens, a sensor housing (212) coupled to the lens barrel, and an image sensor (230) received in the sensor housing.

Abstract: A system according to embodiments of the invention may include a first communication path that converts an optically-modulated source signal to a radio signal based on a detected degradation in a quality of a received optical signal, and a second communication path that converts a radio-modulated source signal to an optical signal based on a detected degradation in a quality of a received radio signal. The system has the ability to automatically adapt to diverse weather conditions to improve the reliability of a communication link without user intervention while supporting multiple modulation schemes.

Abstract: A signal detector system (10) comprises a single signal detector (11) having a limited on-time during which any received electromagnetic signal can be assessed. The signal detector (11) receives electromagnetic signals from a single direction in space (D) through a single optical fibre (12), a signal splitter 13 which splits the collected signal between three optical paths (20, 30 and 40), and a signal combiner (14) which combines the portions of the signal transmitted by the three optical paths (20, 30 and 40) and transmits the combined signal to a signal detector input (15). Each of the optical paths (20, 30 and 40) includes a respective optical delay (21, 31 and 41) designed to delay transmission of any received signal towards the signal detector (11). In this manner the signal detector (11) will receive any signals that arrived at the optical fibre (12) during three separate periods of time.

Abstract: A data transmission system has a light-emitting transmitter, a light-receiving receiver and a data transmission channel based on incoherent light. A pre-equalization device connected upstream of the transmitter is provided for the purpose of pre-equalizing a data signal which is to be transmitted from the transmitter to the receiver via the data transmission channel. The data transmission channel has constant transmission conditions within prescribed limits. The data signal to be transmitted is transmitted using a prescribed maximum bandwidth of the transmitter.

Abstract: Systems and methods of electronic wavefront correction are disclosed. An example method receiving an optical signal representing a wavefront traveling along a plurality of propagation paths, and electronically correcting distortion in the wavefront. An example apparatus includes an receiver and an electronic wavefront corrector. The receiver is configured to coherently receive an optical signal representing a wavefront traveling along a plurality of propagation paths. The electronic wavefront corrector is configured to correct phase distortion in the wavefront.