Abstract: An illuminator including an optical transmission mechanism includes a transmission-side electric circuit for forming electric signals modulated in response to information, a light source for emitting intensity-modulated light in response to the electric modulated signals, optical wavelength conversion means including fluorescent material for converting part of the intensity-modulated light into illumination light, photoelectric conversion means for receiving another part of the modulated light and converting this part into reproduced electric modulated signals and a receiving-side electric circuit for reproducing the information from the reproduced electric modulated signals.

Abstract: A method and system for conveying contextually relevant information to a wireless client are disclosed. More particularly, a transmitter transmits a diffuse infrared signal to a client having an IrDA compliant communication interface. The transmitter communicates with the client by making a link layer in the transmitter compliant with an IrDA link layer running on the client. To perform communication, data is received at the transmitter from a service provider. The data is formatted into an IrDA compliant diffuse infrared signal and transmitted to the client. The client receives the data and parses it to extract contextually relevant information contained therein. The client may reply to the transmitter if a user of the client is interested in a service offered by the service provider. If the service provider receives a reply from the client, the service is made available to client.

Abstract: The present photonic RF generation and distribution system provides a system and method for distributing an RF output signal. The photonic RF distribution system includes two optical sources for generating optical signals. A first optical source (42) is operable to generate a first optical signal having an operating frequency. A second optical source (44) is operable to generate a second optical signal having an operating frequency. A modulator (46) is operable to impress an RF modulation signal on a tapped portion of the first optical signal such that a modulated signal is generated. A first coupler (52) combines the modulated signal with a tapped portion of the second optical signal, thereby forming a combined signal having a difference frequency component. A control photodetector (50) is responsive to the combined signal to generate a tone signal.

Abstract: A communications system for wireless transceiving of information, comprising an optical array subsystem for transceiving optical signals and a millimeter wave subsystem for transceiving millimeter wave signals, and a beam steering controller for controlling the direction of the optical and millimeter wave signals. The communication system may be on a flying platform, such as a satellite and may communicate with multiple remote terminals.

Abstract: A communication system employing optical fibers and a high data rate satellite is utilized to provide high-speed Internet access to various geographic regions. In one aspect, a first teleport station is located geographically separated from a first user. The first teleport station is connected through a network access point to the Internet. The second user communicates through a satellite to the first teleport station to access the Internet. The teleport station and the network access point use a long haul optical fiber.

Abstract: A wireless optical communication systems using two optical transceivers located at the opposite ends of an optical communication line. The optical communication system can be either two-element, when each of the said transceivers contains one optical transmitter (emitter) and one optical receiver, or it can be four-element, where each of the said transceivers contains two optical transmitters and two optical receivers. The output of each of the optical transmitters is a diverging beam of incoherent electromagnetic radiation arranged to have a cross sectional diameter which is larger than the cross sectional diameter of the respective optical receiver at that point on the communication line at which the respective optical receiver is situated. The invention reduces the probability of communication failure, higher noise resistance, and lowers operation and production costs.

Abstract: An optical system may be configured as a receiving or as a transmitting system. As a receiving system, it is configured to receive at least one incident laser beam and project the beam into a spot on an array of actuable elements. The position of the spot is determined by the incident angular direction of the beam. The array is configured to track the position of the spot and at each tracked position of the spot to direct the beam onto an actual element. The actuable element tracks the spot so as to direct the beam onto a fixed path toward an optical receiver. As a transmitting system, it includes an actuable element configured to direct the light output from a laser into a spot on an array of actuable elements. The array is configured to track the position of the spot and at each tracked position of the spot to direct the light into a beam-forming system. The beam-forming system is configured to project the light in a transmitted beam having a variable angular direction.

Abstract: The discrimination phase margin monitor circuit (10) of the present invention comprises a first discrimination circuit (11 and 12) discriminating an input data signal using a clock signal extracted from the input data signal, a second discrimination circuit (13 and 14) discriminating the input data signal using a clock signal with a frequency different from that of the clock and an operation circuit (15 and 16) calculating the exclusive OR of the output signal of the first discrimination circuit and that of the second discrimination circuit and obtaining a phase margin monitor output signal by averaging the exclusive ORs.

Abstract: A system and method for supporting two infrared signaling protocols in a single computing device is provided. The computing system operates in a default mode unless a priority signaling request is generated by an application program. Priority signaling requests are given processing priority, and default mode transmission packets may be dropped during priority mode processing. Handling of dropped default mode packets is relinquished to an upper protocol layer of a network stack, which recovers and sends the dropped transmissions to the infrared device when the computing device returns to the default mode.

Abstract: Ultrafast directional beam switching, using coupled VCSELs is combined with a light modulator to provide information transfer at bit rates of tens of GHz. This approach is demonstrated to achieve beam switching frequencies of 32-50 GHz in some embodiments and directional beam switching with angular differences of about eight degrees. This switching scheme is likely to be useful for ultrafast optical networks at frequencies much higher than achievable with other approaches. A Mach-Zehnder interferometer, a Fabry-Peror etalon, or a semiconductor-based electro-absorption transmission channel, among others, can be used as a light modulator.

Abstract: A method and apparatus for processing a data signal for transmission to a remote device transmits at least two synchronized copies of the data signal, in optical form, in different directions. To that end, the data signal first is synchronized to a clock signal to produce a composite signal. The composite signal then is converted to an optical signal, which is referred to as an “outgoing signal.” A plurality of copies of the outgoing signal then are transmitted. At least two copies of the outgoing signal are transmitted in different directions.

Abstract: The extended range of optical data communication is enabled through the use of intermediary relay stations spaced fairly far apart. IRDA communicatiOn, as is well known, uses very short duration optical pulses to send data up to 1 Mbit/sec; this has the concomitant effect of minimizing LED duty cycle and preventing excessive heating. The invention uses a number of integrated pulses to represent a single bit instead of utilizing a one-to-one correspondence between pulses and bits. Processing software causes the transmitter to “stutter” or repetitively emanate the identical pulse representing a bit of information. Sufficient photons are thereby gathered at a receiver to reach a predetermined threshold. A tradeoff of the data transmission frequency in this invention is that as signal intensity drops by a factor of 100 when distance increases by a factor of 10 yielding a distance/intensity ratio of 1/10.

Abstract: The present invention is a method and system for transmitting data between two objects via a free space optical data link. In an exemplary aspect of the present invention, the method may start with a step in which a laser beam modulated with data is transmitted to the vicinity of an optical collector. The laser beam may be transmitted by a modulated laser transmitter. The laser beam may cause atmospheric nitrogen in the vicinity of the optical collector to fluoresce and emit a set of characteristic line spectra. The set of characteristic line spectra may be received by the optical collector, and at least one characteristic spectral line may be obtained with an optical filter. Preferably, a wavelength of the at least one characteristic spectral line is selected from a group consisting of 3995.00 angstroms, 4630.54 angstroms, 5005.15 angstroms, and 5679.56 angstroms, which have high relative amplitude.

Abstract: An interrogator identifies an interrogated object using a light transceiver and a dynamic optical tag associated with the interrogated object. The dynamic optical tag receives an output light beam from the light transceiver and controllably reflects the light beam back to the light transceiver as an input light beam. The dynamic optical tag includes a controllable light reflector that is controllable between a reflective state and a non-reflective state and having a modulation signal input, and a controller that provides the modulation signal input to the controllable light reflector. In operation, the interrogator transmits an interrogation light beam from the light transceiver to the dynamic optical tag, the dynamic optical tag reflects a modulated interrogation light beam back to the light transceiver as the input light beam, and the light transceiver receives and analyzes the input light beam to determine an identity of the dynamic optical tag and the interrogated object.

Abstract: An optical communication device having multiple light sources under a single lens. The optical communication device has two light sources. The optical communication device has a lens optically coupled to the two light sources. The lens is shaped to direct light from the two light sources towards an axis of the lens. The optical communication device further has a third light source located below the approximate center of the lens.

Abstract: A communication system includes a plurality of nodes and a plurality of point-to-point links that interconnect the plurality of nodes into a network. Each node includes an optical switch to controllably route a plurality of in-ports of the optical switch into a plurality of out-ports of the optical switch. Each point-to-point link includes a free space optical channel. A first free space optical channel couples to a first node through a receive path and through a transmit path. The receive path couples to a respective in-port of the optical switch of the first node, and the transmit path couples to a respective out-port of the optical switch of the first node. In an alternative embodiment, a communication hub includes a plurality of neighborhood links to corresponding users, an optical switch coupled to the plurality of neighborhood links, and a trunk coupled between the optical switch and a free space optical channel link to the network.

Abstract: Free-space optical (FSO) laser communication systems offer exceptionally wide-bandwidth, secure connections between platforms that cannot other wise be connected via physical means such as optical fiber or cable. However, FSO links are subject to strong channel fading due to atmospheric turbulence and beam pointing errors, limiting practical performance and reliability. We have developed a fade-tolerant architecture based on forward error correcting codes (FECs) combined with delayed, redundant, sub-channels. This redundancy is made feasible though dense wavelength division multiplexing (WDM) and/or high-order M-ary modulation. Experiments and simulations show that error-free communications is feasible even when faced with fades that are tens of milliseconds long. We describe plans for practical implementation of a complete system operating at 2.5 Gbps.

Abstract: Dispersion compensation values are set so as to be transmittable to any path groups in a WDM optical communication system having OADM nodes, which includes transmitting-end and receiving-end terminal nodes; a WDM optical communication transmission line including a plurality of spans each having an optical fiber, the plurality of spans joining the transmitting-end and receiving-end terminal nodes; and a plurality of add drop multiplexing (OADM) nodes disposed on the optical communication transmission line; wherein when taking as the reference a residual dispersion target value of between the transmitting-end terminal and receiving-end terminal nodes, a residual dispersion target value for a node segment between one of the terminal nodes and one of the add drop multiplexing (OADM) nodes and a residual dispersion target value for a node-to-node segment between two of the add drop multiplexing (OADM) nodes are set so as to be proportional to ratios of the span counts in the node segment and in the node-to-node se

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: Methods and apparatus for monitoring the power level of one or more optical emitters are provided. In some embodiments, optical signals from two or more optical emitters are directed at different regions of a photo detector. The photo detector may include two or more spaced contacts that are adapted to receive different contributions of photo current from each of the optical signals. By monitoring the photo currents in the two or more spaced contacts, a measure of the optical power of each of the optical signals may be determined.

Abstract: An optical space communications device includes a transmitter circuit which assigns an idle code indicating that the device is transmitting no data so that the idle code differs from an idle code for another device and which, when the transmitter circuit continuously transmits such idle codes, inserts, between the idle codes, a random code having a different random pattern from a pattern of the idle codes. Thus, light from another device is distinguished from stray light based on the idle codes. A disconnection of the other device is reliably detected. The insertion of random codes reduces effect of crosstalk jitter.

Abstract: A method and apparatus for controlling a plurality of infrared devices (ICDs) is provided herein. A remote controller is used to generate an optical signal for controlling a plurality of ICDs. The optical signal generated by the remote controller is converted into an electrical signal by an infrared repeater device. An implementation of such a system includes a rotary mechanical switch to direct the electrical signal generated by the infrared repeater device to a light emitting diode (LED) located near one of the plurality of ICDs. The LED converts the electrical signal into an optical signal and re-transmits the optical signal to the one of the plurality of ICDs. The system allows controlling the plurality of ICDs located in a remote location without having the user commute closer to such ICDs.

Abstract: An optical communication system is provided which includes an optical signal transmitter which communicates high bandwidth, high power frequencies. The optical signal transmitter includes a high efficiency/high power optical source such as an optical magnetron or a phased array source of electromagnetic radiation, and a modulator element. The modulator element may be within a resonance cavity of the high efficiency/high power optical source (intra cavity) or external to the cavity (extra cavity). The modulator element serves to modulate output radiation of the high efficiency/high power optical source to produce a modulated high frequency optical signal which may be transmitted through the air. The optical signal transmitter is particularly useful in providing the last mile connection between cable service operators and end users.

Abstract: A distributed multi-drop base station/repeating unit using an extension of analog optical transmission in a mobile communication system. The base station unit comprises a main unit for performing functions of a mobile communication base station, and a plurality of remote units cascaded to the main unit on a sector basis.

Abstract: An apparatus and method for conveying contextually relevant information to a wireless client (112) is disclosed. More particularly, an emitter (108) transmits a diffuse infrared signal to a client (112) having an IrDA infrared communication interface (130). Emitter (108) communicates with client (112) by making a link layer in emitter (108) compliant with an IrDA link layer running on client (112). To perform communication, data is received at emitter (108) from a service provider (102). The data is formatted into an IrDA compliant diffuse infrared signal and transmitted to client (112). Client (112) receives the data and parses it to extract contextually relevant information contained therein.

Abstract: The invention relates to a system for conveying digital signals inside a space vehicle between a transmitter and a receiver. In the invention, the link between the transmitter and the receiver comprises a first portion made of optical fiber and a second portion in which infrared radiation propagates without guidance. A particular application lies in conveying remote control and telemetry signals within a satellite between a control module and a piece of equipment.

Abstract: An optical transceiver is equipped with at least one coupling lens which condenses reception signal light from an optical medium and condenses transmission signal light to the optical medium, an optical plate which passes the reception signal light and reflects the transmission signal light, a light receiving element which receives the reception signal light passed through the optical plate, and a light emitting element which transmits the transmission signal light so as to be reflected by the optical plate, wherein an emission port of the transmission signal light of the light emitting element is arranged at a position to enable the transmission signal light from the light emitting element to form an image in the optical medium via the optical plate and the coupling lens, and wherein the emission port of the transmission signal light of the light emitting element is arranged in a direction that makes the incident angle formed on the optical plate by the beam center line of the transmission signal light trans

Abstract: The present invention is directed to a laser communication receiver for wireless optical communication. A laser communication receiver includes a diffractive optical element to permit detectors at different spatial locations to detect different wavelengths of the optical signal. An immersion lens may be employed to focus the optical signal to a spot size smaller than the photoactive area of the detector. In one detector configuration, the optical signal is folded by a reflective surface and focused on a plurality of stacked detectors. The present invention further provides a method of manufacturing a detector and immersion lens assembly that provides a high degree of alignment between the lens and the corresponding detector.

Abstract: A system for time-dividing an optical signal is provided. The system time-divides a signal and reflects and/or refracts the signal using a time-dividing device to multiple receivers. By using time-division, the full signal is sent to each receiver designated to receive the signal during a certain time period. A cost effective and efficient system is provided by time-dividing the optical signal.

Abstract: An optical transceiver having a transmitter section and a receiver section formed on a substrate to be close to each other is provided, which suppresses the electrical and optical crosstalk between the transmitter section and the receiver section. The transceiver comprises: (a) a substrate; (b) a transmitter section formed on the substrate and including a light-emitting element; (c) a receiver section formed on the substrate to be close to the transmitter section and including a light-receiving element; (d) a conductive first connection member fixed near the substrate; and (e) a transparent second connection member fixed near the first member in such a way as to block the first opening and the second opening of the first member from a front of the first member. The first member has a first opening that allows a first light beam to penetrate the first member and a second opening that allows a second light beam to penetrate the first member.

Abstract: Internal communication signals in a stored program controlled system comprising a plurality of units configured to process signals are provided by an optical beam line which is proximal to all of the plurality of units. The system of this invention uses Space Division Multiplexing techniques to provide a plurality of logically independent subchannels over a single, shared free space optical beamline.

Abstract: A MEMS-based optical, wireless communication system (10) that is comprised of a receiving and transmitting optical unit (12) that is further comprised of a transmitting subsystem (14) and a receiving subsystem (60), both of which are controlled by a microcontroller (16) and firmware (96). The system (10) is designed to allow a first unit (12) to transmit through free space a modulated laser beam (39) that is received by a second unit (12) located within line-of-sight of the first unit (12). Conversely, the second unit (12) can likewise transmit a modulated laser beam (39) that is received by the first unit (12) or other line-of-sight units (12). The system (10) features a MEMS mirror assembly (34) that operates in combination with a quad sensor (100). The combination allows fast, precise tracking and compensates for atmospheric disturbances associated with optical communication namely, building sway, wind and scintillations caused by changes in the refraction index of the atmosphere.

Abstract: A digital data network uses network nodes incorporating infrared transceivers. Each node includes a plurality of infrared transceivers having transmitter and receiver optics designed to facilitate line-of-sight infrared optical communications in a residential or business neighborhood. New nodes are installed with at least one selected transceiver having line-of-sight access to at least one existing transceiver. Automated tracking and acquisition processes are used to align transceivers to enable data communication and to acquire newly installed nodes into the network. Other automated tracking programs operate on an as-needed or scheduled basis to maintain good alignment and communications between adjoining node transceivers. Network nodes include weather-proof housings and are of a size and shape to be easily mounted on existing structures so as not to disrupt the visual appeal of a neighborhood.

Abstract: A system and method for efficiently and effectively simulating hardware-in-the-loop testing of a wireless communications network. The system and method employs an optical matrix-vector multiplier (MVM) for performing optical signal processing to simulate radio frequency (RF) signal propagation characteristics in a mobile wireless communications network. Specifically, the system and method employs an optical modulator, which is adapted to modulate optical energy with signal energy, such as radio frequency (RF) signal energy, propagating from a first group of transceivers of the network to form a vector of optical signals. The optical matrix-vector multiplier (MVM) receives the vector of optical signals, and has a matrix of optical channel weights which are modifiable in accordance with desired parameters to represent at least on parameter of the wireless network. The optical MVM is further adapted to output signals based on the received vector of optical signals and the optical channel weights.

Abstract: In an optical wireless network, where light beams are transmitted over-the-air, reflections of the transmitted light beams may cause a receiver of an optical wireless device to detect and subsequently lock onto the signal that it transmitted. By doing so, the network is effectively broken. A method and apparatus to detect the reception of reflected signals using minimal additional hardware and data is presented. Should a reflected signal be detected, the receiver is prevented from locking onto the signal, allowing the receiver to detect and subsequently lock onto light beams originating from other optical wireless devices.

Abstract: An Improved Infrared Signal Communication System and Method Including Transmission Means Having Automatic Gain Control is disclosed. Also disclosed is system and method that adjusts signal transmission power in response to incident signal power amplitude. The preferred system includes a control signal loop within the signal receiving system, and the system further includes a signal transmitting system that is responsive to the control signal loop. The preferred system includes manual, semi-automatic and automatic modes of operation. Still further, the preferred method includes at least two Ir-enabled appliances “stepping” each other “down” in transmit power in response to directives issued by the other Ir-enabled appliance.

Abstract: The present invention provides a method and apparatus for free-space optical communication. The method comprises the steps of receiving a receive optical beam through a narrow field of view, determining a receive power level, shifting an alignment, maximizing the receive power, and transmitting a transmit optical beam along the alignment, wherein the narrow field of view is less than a divergence of the transmit optical beam. The narrow field of view can be a narrow region of a multi-region field of view. The apparatus comprises an optical beam transmitter configured to generate a narrow diverging transmit beam, a narrow field of view optical receiver, wherein the field of view is less than the divergence of the transmit beam, and a controller configured to determine a power level of a receive beam and to determine adjustments to a direction of transmission maximizing receive power.

Abstract: A free space optical tap and multi/demultiplexer unit includes at least one optical unit that can tap off an optical signal from and/or add an input optical signal to a received FSO signal. The optical unit propagates the resulting optical signal, via free space, to a next optical unit of the system. The optical unit can include a holographic grating to diffract a portion of the received FSO signal to an optical detector and/or diffract an input optical signal to form part of a free space optical output signal. In addition, the FSO signal can include component signals of different wavelengths, with each optical unit of the system being wavelength specific to a different one of the wavelengths of the FSO signal.

Abstract: This invention provides a dynamic interconnection system which allows to couple a pair of optical beams carrying modulation information. In accordance with this invention, two optical beams emanate from transceivers at two different locations. Each beam may not see the other beam point of origin (non-line-of-sight link), but both beams can see a third platform that contains the system of the present invention. Each beam incident on the interconnection system is directed into the reverse direction of the other, so that each transceiver will detect the beam which emanated from the other transceiver. The system dynamically compensates for propagation distortions preferably using closed-loop optical devices, while preserving the information encoded on each beam.

Abstract: A hybrid wireless optical and radio frequency (RF) communication link utilizes parallel free-space optical and RF paths for transmitting data and control and status information. The optical link provides the primary path for the data, and the RF link provides a concurrent or backup path for the network data, as well as a reliable and primary path for the control and status information. When atmospheric conditions degrade the optical link to the point at which optical data transmission fails, the hybrid communication link switches to the RF link to maintain availability of data communications. The switch may occur automatically, based on an assessment of the quality of the optical signal communicated through the optical path.

Abstract: The present invention provides an apparatus and method for free-space optical communication. The apparatus includes a first board with a plurality of optoelectronic converter components mounted on the first board. The apparatus additionally includes at least one optics element optically aligned with at least one of the optoelectronic converter components, where the optics element is configured to pass light directly between free-space and the plurality of optoelectronic converter components, and electronics coupled to at least one of the plurality of optoelectronic converter component. In one embodiment, communication is achieved by providing electric signals to a plurality of lasers that are mounted on a first board, generating a plurality of optical signals with the plurality of lasers and directing the plurality of optical signals into free-space with a plurality of optics elements.

Abstract: A satellite constellation has a plurality of satellites. Each of the satellites has an RF ground link for communicating with a ground station and an optical link for communication with at least one of the plurality of satellites. Each of the satellites has a reconfigurable optical transmitter for sending and receiving data streams. Each reconfigurable optical transmitter has a first optical carrier associated therewith and a reconfigurable optical receiver. The plurality of satellites is arranged to have a first subset of satellites. The first subset of satellites is configured to communicate. The plurality of satellites is reconfigured to have a second subset of satellites having at least one different satellites than that of said first subset. The second subset supercedes the first subset. The second subset of satellites is configured to communicate. Various subset around the globe may form local area networks. The local area networks are preferably optically coupled to form a wide area network.

Abstract: A communication system includes a plurality of nodes and a plurality of point-to-point links that interconnect the plurality of nodes into a network. Each node includes an optical switch to controllably route a plurality of in-ports of the optical switch into a plurality of out-ports of the optical switch. Each point-to-point link includes a free space optical channel. A first free space optical channel couples to a first node through a receive path and through a transmit path. The receive path couples to a respective in-port of the optical switch of the first node, and the transmit path couples to a respective out-port of the optical switch of the first node. In an alternative embodiment, a communication hub includes a plurality of neighborhood links to corresponding users, an optical switch coupled to the plurality of neighborhood links, and a trunk coupled between the optical switch and a free space optical channel link to the network.

Abstract: A point-to-multipoint bi-directional wide area telecommunications network employing atmospheric optical communication. The network comprises a primary transceiver unit, a plurality of subscriber transceiver units and an optical router. The primary transceiver unit may send data destined for the subscriber transceiver units through the optical router, and the subscriber transceiver units may send data destined for the primary transceiver unit through the optical router. The primary transceiver unit and optical router communicate by means of light beams which are transmitted through the atmosphere. Similarly, the optical router and the subscriber transceiver units communicate by means of light beams which are transmitted through the atmosphere.

Abstract: A method of transmitting data in a wireless power transmission system comprising a power transmitter including a first and a second light source and means for directing the emitted light. The second light source is used for transmitting, parallel and as low-intensity pulses, light arranged around the light emitted by the first light source, data bits being encoded in the pulses so as to determine a maximum time interval between two successive pulses. At least one power receiver of the system comprises a first and a second photo-detector for receiving the emitted light and for converting it into electric current. The second photo-detector is used for indicating light pulses and data included therein and time between successive light pulses. A control signal indicating disturbance-free reception of data is transmitted to the transmitter if the time between successive light pulses does not exceed a predetermined maximum time interval.

Abstract: A repeater apparatus (1001) is constituted from infrared transmitter sections (1s, 2s, 3s) and infrared receiver sections (1r, 2r, 3r) as well as connection control sections (1C, 2C, 3C) and further a repeater section (101), thereby attaining independent communications with the individual one of several associated equipments with respect to infrared communication apparatus of the direct emission type which supports only one-to-one (1-to-1) or one-to-several (1-to-N) communication schemes, thus enabling achievement of N-to-N communication forms by performing transfer of data information being received by each communication equipment to others.

Abstract: The present invention is directed to a laser communication transmitter and receiver for wireless optical communication. The laser communication transmitter uses a small diameter so correspondingly divergent beam to provide improved bit error rates. A laser communication receiver includes a diffractive optical element to permit detectors at different spatial locations to detect different wavelengths of the optical signal. An immersion lens may be employed to focus the optical signal to a spot size smaller than the photoactive area of the detector.

Abstract: A free-space optical communication apparatus includes a storage unit which stores angle-setting information for the mirror for communicating with each of the plurality of other apparatuses, a mirror driving unit which drives the mirror to an angle corresponding to the stored angle-setting information, an optical detecting unit which, on one occasion for communicating with a specified communication apparatus among the plurality of other apparatuses, detects the incident state of an optical beam sent from the specified apparatus, and a control unit which, based on the detected incident state of the optical beam, determines angle-correcting information for correcting the stored angle-setting information for the specified apparatus, and which, on the next occasion for communicating with the specified apparatus, uses the mirror driving unit to drive the mirror to an angle corresponding to the angle-setting information corrected by the angle-correcting information.

Abstract: A light emitting diode (LED) warning signal light and communication device comprising a controller for generating a first observable light signal and a second non-observable light signal within said first light signal. The second light signal is formed of packets of individual pulsed light which may be processed for comparison to data stored in memory integral to a controller for communication of information to an individual through the use of pulsed light signals.

Abstract: Various embodiments of apparatus and various embodiments of methods to communicate between a first circuit board and a second circuit board using one or more open air communication channels are provided. A plurality of light transmitters and light receivers are attached to a first circuit board; and a corresponding plurality of light receivers and light transmitters are attached to a second circuit board. The light receivers on both circuit boards are disposed to receive data transmitted by the corresponding light transmitters on each circuit board. In one embodiment, where the light transmitters are laser diodes, different colors may be used to increase adjacent signal rejection. In another embodiment, the light transmitters may be laser, radio, microwave, digital, ultraviolet, or infrared light transmitters. The light transmitters may transmit data across open spaces between circuit boards, including through apertures in boards placed between the light transmitter and light receiver.