Abstract: A method, apparatus, and system for optical communications. An optical transmit signal is generated in response to an electrical transmit signal. The optical transmit signal is coupled into a single communication link for transmission there over. An optical receive signal is received from the single communication link, and in response an electrical receive signal is generated.

Abstract: An optical communications system includes a receiver subsystem with at least two heterodyne receivers. The receiver subsystem receives a composite optical signal having two or more subbands of information and corresponding tones. An optical splitter splits the composite optical signal into optical signals. Each optical signal includes a subband(s) and corresponding tone. Each heterodyne receiver receives an optical signal. The receiver includes a heterodyne detector coupled to a signal extractor. The heterodyne detector mixes the optical signal with an optical local oscillator to produce an electrical signal which includes a frequency down-shifted version of the subband and the tone of the optical signal. The signal extractor mixes the frequency down-shifted subband with the frequency down-shifted tone to produce a frequency component containing the information.

Abstract: A frequency-agile optical transceiver includes a shared local oscillator (LO), a coherent optical receiver and an optical transmitter. The LO operates to generate a respective LO optical signal having a predetermined LO wavelength. The coherent optical receiver is operatively coupled to the LO, and uses the LO signal to selectively receive traffic of an arbitrary target channel of an inbound broadband optical signal. The optical transmitter is also operatively coupled to the LO, and uses the LO to generate an outbound optical channel signal having a respective outbound channel wavelength corresponding to the LO wavelength.

Abstract: A package to encapsulate an optical component includes a RF interface to receive high frequency signals from an external source. The RF interface pins that can be configured as one or more single-ended transmission lines or as one or more differential transmission lines. For example, the RF interface includes four pins that can be coupled in one of two configurations to provide a single-ended transmission line and in a third configuration to provide a differential transmission line. In one embodiment, the first, second, and fourth pins are coupled to ground while the second pin is coupled to receive a RF signal. Alternatively, the first, second and fourth pins are coupled to ground and the third pin is coupled to receive a RF signal. For a differential transmission line, the first and fourth pins are coupled to ground while the second and third pins are coupled to receive a differential RF signal.

Abstract: The optical communication multiplex device for a vehicle comprises optical communication lines connecting a transmitting terminal (Tx) to a receiving terminal (Rx). Contact resistances are disposed near the optical communication line to generate heat for changing the length of the optical communication lines. A power terminal and a ground terminal are respectively connected to one end and the other end of the contact resistances to thereby supply power to the contact resistances. A control terminal outputs a control signal for changing the length of the optical communication lines via the contact resistances supplied with power from the power terminal. A transistor connected between the control terminal and the contact resistances carries out a switching operation of power applied to the contact resistances from the power terminal in response to the control signal inputted from the control terminal.

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: The invention relates to a communications backbone interface between at least three members of a communications network for a space vehicle. In the invention, the interface combines various signals received at inlets, which signals may be analog, digital, and optical, coming from two members, and produces a multiplexed optical signal for delivery to a member of the vehicle, such as a piece of equipment. The invention also provides to a communications terminal interface, a communications network having such interfaces, and an optical fiber harness.

Abstract: This optical clock phase-locked loop circuit includes an oscillator 12, an optical coupler 2, an optical cross-correlation detection device 3 that outputs light containing the correlating components of two lights from the coupled light of optical coupler 2, an optical band pass filter 4 that extracts light of a wavelength that contains cross-correlating components, an optical receiver 5, a phase comparator 6 that compares the phases of the output signal of the oscillator 12 and the cross-correlation signal from the optical receiver 5, a voltage controlled oscillator 7 that changes the oscillation frequency and phase corresponding to the output of the phase comparator 6, an optical pulse generator 8 that generates a optical clock pulse containing an nth harmonic component, an optical coupler 10 that divides optical clock, and an optical modulator 11 driven by low-frequency oscillator 12 that modulates optical clock from optical coupler 10.

Abstract: A transmitter subsystem generates an optical signal which contains multiple subbands of information. The subbands have different polarization. For example, in one approach, two or more optical transmitters generate optical signals which have different polarization. An optical combiner optically combines the optical signals into a composite optical signal for transmission across an optical fiber. In another aspect, each optical transmitter generates an optical signal containing both a lower optical sideband and an upper optical sideband (i.e., a double sideband optical signal). An optical filter selects the upper optical sideband of one optical signal and the lower optical sideband of another optical signal to produce a composite optical signal.

Abstract: An optic semiconductor package includes a main board of a substantially planar plate shape. The main board includes an aperture therethrough and a plurality of board metal patterns formed at the periphery of the aperture. A package portion is coupled to the main board. The package portion includes a base, a laser diode and a photo detector electrically coupled to the board metal patterns of the main board and bonded to the base. An optical fiber is inserted into the aperture of the main board and disposed adjacent the package portion. The position and tilt of the optical fiber may be adjusted to achieve optimum optical coupling between the optical fiber and the laser diode and the optical fiber and the photo detector. The optical fiber is stably attached to the main board by an adhesive.

Abstract: An electro-optic clock recovery circuit comprising an electro-optic modulator circuit operatively coupled to; a photodetector circuit; a buffer circuit operatively coupled to said photodetector circuit; a voltage controlled oscillator operatively coupled to said buffer circuit and to said electro-optic modulator circuit; wherein the electro-optic modulator circuit receives and modulates a multi-channel input data stream, the photodetector circuit responsive to the modulated input data stream drives the voltage controlled oscillator in a phase locked loop through the buffer circuit, and the modulator circuit is responsive to the voltage controlled oscillator and is driven at a harmonic of the voltage controlled oscillator.

Abstract: A card for transmitting data over at least one optical fiber includes a transmitter having at least one light source and a phase modulator for phase modulating light from the source so as to create phase-modulated optical signals in the light as a function of an input electronic data stream; and a receiver having an interferometer for reading received optical signals.

Abstract: A transmitter comprises an oscillator, a phase lock loop, a serializer, and an electrical-to-optical converter. The oscillator is enclosed in a metal shield. The metal shield is soldered to a ground ring of the printed circuit board. In one embodiment, the oscillator is voltage-controlled oscillator.

Abstract: A system for optical communication send optical signals over a plurality of wavelength channels. Each wavelength channel comprises a number of orthogonal subchannel frequencies which are spaced apart from one another by a predetermined amount. Each of the subchannel frequencies is modulated with data from a data stream. The data modulation scheme splits a subchannel frequency code into H and V components, and further processes the components prior to modulation with data. The various data-modulated subchannels are then combined into a single channel for transmission. The received signals are detected and demodulated with the help of a symbol timing recovery module which establishes the beginning and end of each symbol. A polarization mode distortion compensation module at the receiver is used to mitigate the effects to polarization more distortion in the fiber.

Abstract: In an ultrahigh-speed clock extraction circuit wherein a local pulse generating light source 22 for generating a local optical pulse stream synchronized in bit phase with an input optical signal pulse stream is placed in a phase-locked loop, when repetition frequencies of the input optical signal pulse stream and the local optical pulse stream bear a particular relationship, a frequency demultiplier 32 and multipliers 43 and 52 are set so that the frequency of a modulation signal for an optical modulator 41 and a frequency which is a natural-number multiple of the modulation signal frequency, and the frequency of a down-converted version of an optical pulse stream output from a photodetector 42 differ from each other.

Abstract: An optical transceiver providing a carrier; a cover couplable to a portion of the carrier to define a transceiver enclosure; and, an electro-optical assembly supported in the enclosure is provided. A coupling mechanism and cooperating structure are particularly adapted to define pivoting motion of the cover relative to the carrier, whereby interference of the cover and the electro-optical assembly is avoided. Methods of assembling the transceiver components are present.

Abstract: The present electromagnetic signal sensing system includes a modulating circuit for generating an electrical modulating signal, a laser electrically connected to the modulating circuit, an optically modulated scatterer coupled with the laser, a receiving antenna, a synchronous detection circuit electrically connected to the receiving antenna and a signal processing circuit electrically connected to the synchronous detection circuit. The laser generates an optical modulating signal based on the electrical modulating signal for modulating the optically modulated scatterer to generate a modulated scattering signal. The receiving antenna receives the modulated scattering signal, the synchronous detection circuit generates an in-phase signal and a quadrature-phase signal with a phase offset of 90 degrees from the electrical modulating signal, and the signal processing circuit calculates the amplitude and phase of the electromagnetic signal from the in-phase signal and the quadrature-phase signal.

Abstract: A synchronized optical clocking signal is provided to a plurality of optical receivers by providing a layer of a high absorption coefficient material, such as SiGe or Ge, on a front surface of a low absorption coefficient substrate, such as silicon. Diodes are formed in the germanium containing layer for receiving an optical signal and converting the optical signal into an electrical signal. An optical clocking signal is shined on the back surface of the silicon substrate. The light has a wavelength long enough so that it penetrates through the silicon substrate to the germanium containing layer. The wavelength is short enough so that the light is absorbed in the germanium containing layer and converted to the electrical clocking signal used for neighboring devices and circuits. The germanium concentration is graded so that minority carriers are quickly swept across junctions of the diodes and collected.

Abstract: Generating oscillator signals with which selected signals may be mixed. Such oscillator signals may be generated by dividing a pilot tone, such as a 120 MHz pilot tone found on many cable TV systems. Oscillator signals for demodulating received selected signals may be similarly generated.

Abstract: A frequency translating device (FTD) includes at least one light-activated resistor (LAR) connected to down-convert a radio frequency (RF) to an intermediate frequency (IF) and to up-convert an IF to an RF and a source of modulated light that is optically connected to the LAR. The source of modulated light is modulated in response to a local oscillator (LO) and the LAR is activated in response to the modulated light. Modulated light can be generated from a light source and an LO by, for example, directly modulating the light source, modulating a transmission switch that blocks the transmission of light to the LAR, or modulating a light path switch. The LAR-based FTD can be used as a reciprocal FTD to characterize another FTD in a three-pair measurement system. An FTD may include more than one LAR to form, for example, single-balanced and double-balanced LAR-based FTDs.

Abstract: A method and apparatus are provided for transmitting and receiving multiple RF/microwave subcarriers on a single optical wavelength over an optical link. The method includes the steps of modulating a plurality of RF/microwave subcarrier frequencies with a respective communication signal and modulating an optical carrier wave with the plurality of modulated RF/microwave subcarrier frequencies.

Abstract: An multiplex transmission apparatus that realizes a receiving system using a phased array antenna with high efficiency and low cost is provided. A delay controller 102 gives a time delay to a local oscillation signal outputted from a signal source 101. First and second optical transmitters 1031 and 1032 each converts the local oscillation signal and the delayed local oscillation signal into optical signals. A first optical multiplexer 104 multiplexes the optical signals for transmission. An optical separator 106 separates the multiplexed optical signal. A first multiplexer 1071 multiplexes first and second main element signals, while a second multiplexer 1072 multiplexes first and second sub-element signals. First and second optical modulators 1081 and 1082 each modulates the optical signal with multiplexed electrical signal group. A second optical multiplexer 109 multiplexes the modulated optical signals for transmission.

Abstract: An optical transmission system of the present invention includes at least one transmitter configured to receive information from a plurality of optical receivers and transmit the information in a plurality of information carrying optical signal wavelengths. At least one optical receiver is configured to receive a plurality of information carrying optical signal wavelengths and a local oscillator signal. The optical receiver converts a plurality of optical signal wavelengths into a corresponding number of electrical signal frequencies. The optical systems reduce the number of transmitters and receivers required interconnecting various optical systems, as well as providing multiple wavelength regenerators and converters and add/drop devices with increased capacity and system flexibility.

Abstract: Plural subcarrier-multiplexed AM signals 30 are input and narrow-band-FM-modulated by a voltage controlled oscillator 4 including the fundamental carrier wave and higher-order harmonics as the output, and the FM carrier wave component of the higher-order harmonics of the fundamental carrier wave is selectively taken out by a band-rejection filter 5, shifted to the lower frequency side by a frequency converter 7, converted into an optical signal by an electric/optic converter 3 and transmitted.

Abstract: The invention concerns a computer system (1), preferably of the personal microcomputer type, controlled by a group of users by means of several mouse-type pointing devices (3) without wired connection with the system (1). Each pointing device communicates by infrared with a console (38) connected to the system (1) through a communication port (50). A multifrequency transmission technique and a frequency hopping coding are used. The graphic interface of the system is projected (47, 48) on a large screen (49) for collective visual display. The console (38) comprises a detachable receiver horn (41) which enhances the range, and a set of switches (40) for selecting the mouse or mice controlling one or several cursors (54) of different shape and/or colour. The inventive device is particularly designed for collective initiation to microcomputing and collective training in using software.