Abstract: There is provided an optical transmitting device including a detector to detect a transmission rate of a transmission signal, a transmission method selector to determine a transmission method of the transmission signal, based on the transmission rate detected by the detector, a modulation signal generator circuit to generate a modulation signal from the transmission signal, based on the transmission method determined by the transmission method selector, and an optical modulator to generate a modulated optical signal from the modulation signal generated by the modulation signal generator circuit.

Abstract: A system configured to maintain a consistent local-oscillator-power-to-primary-signal-power ratio (LO/SIG ratio).

Abstract: In a communication device using a plurality of signal enhancement mechanisms, a system and method are provided for managing signal processing power consumption. A receiver accepts a communications signal and analyzes signal integrity. In response to analyzing the signal integrity, a signal enhancement mechanism is changed, and device power consumption is modified in response to changing the signal enhancement mechanism. In one aspect, the receiver changes a receiver signal enhancement mechanism, and modifies its power consumption. For example, one or more of the following receiver signal enhancement mechanisms may be selected: forward error correction (FEC), equalization, dc voltage level, and physical coding sublayer (PCS).

Abstract: Embodiments of the present invention disclose a method, a device, and a system for saving energy in optical communication. The method includes the following: sending first information to an optical communication device at a peer end through the optical module by using a first transmit optical power; receiving, through the optical module, second information that is returned by the optical communication device at the peer end after it receives the first information; and reducing, according to the first transmit optical power, and a receive optical power value and minimum receive optical power value in the received second information, the transmit optical power value of the optical module of the optical communication device to a difference value between the first transmit optical power value and the receive optical power value plus the minimum receive optical power value of the optical communication device at the peer end and a margin value.

Abstract: A device receives, from an optical receiver, performance information associated with an optical channel generated by an optical transmitter, and determines, based on the received performance information, a wavelength that minimizes polarization mode dispersion (PMD) associated with the optical channel. The device also provides, to the optical transmitter, a request to adjust an optical channel wavelength to the determined wavelength.

Abstract: Consistent with the present disclosure, an optical receiver is paired with an optical transmitter in a transceiver card or module, for example. During normal operation, the optical transmitter supplies optical signals for downstream transmission on a first optical communication path, and the optical receiver receives additional optical signals from a second optical communication path. During a transmitter monitoring mode (or “loopback”), however, when monitoring of transmitter parameters is desired, an optical switch directs the output or portion thereof from the transmitter to the receiver. The receiver may then supply monitoring data or information to a control or processor circuit, which, in turn, may supply control signals to the transmitter. In response to such control signals, the performance of the transmitter may be optimized, for example, by reducing BER and/or OSNR to a desired level.

Abstract: An optical transmission system includes: a two-lightwave generator for generating optical signals having wavelengths ?1 and ?2 from laser light; a photodetector for detecting a microwave signal M12 from two optical signals distributed by an optical coupler; an optical modulator for frequency-shifting the two optical signals; a Faraday reflector for reflecting the two optical signals; an optical coupler for mixing the two optical signals that have been reflected by the Faraday reflector, frequency-shifted again, transmitted by an optical fiber, and guided by a polarization beam splitter, with two optical signals distributed by an optical coupler; an optical demultiplexer for wavelength-dividing four mixed optical signals into optical signals having the wavelengths ?1 and ?2; photodetectors for detecting respective beat signals of the wavelength-divided optical signals having ?1 and ?2; and a phase difference detector for detecting a phase difference between the beat signals of the optical signals having ?1 and

Abstract: A waveform controller includes a monitor configured to monitor a waveform of an output pulse obtained by the response of a responsive element to a driving signal supplied thereto and a driving waveform shaper configured to shape a waveform of the driving signal based on a monitoring result obtained by the monitor.

Abstract: An equalization filter is provided for solving the problem in which there is a limited range in which compensated for distortion of a transmission signal can be made. Measuring instrument 104 measures a distortion quantity which characterizes distortion of the transmission signal. Comparator 105a generates a differential signal which indicates the difference between the transmission signal and a compensation signal. Delay device 105b delays the differential signal based on the distortion quantity measured by measurement instrument 104 and generates the compensation signal.

Abstract: Disclosed is a method for setting a power control initial value by using an indication light in visible light communications and a transmission/reception (Tx/Rx) apparatus using the method. The method includes the steps of: radiating multiple indication lights having power levels different from one another by a visible light communication transmitter; aligning a communication position simultaneously with measuring Received Signal Strength Indication (RSSI) of the indication light on detecting the indication light, selecting a power level whose RSSI is in a preset threshold range and which is adequate for transmission/receive among the multiple power levels different from one another, and informing the visible light communication transmitter of the adequate power level by a visible light communication receiver; and transmitting data from the visible light communication transmitter to the visible light communication receiver by using a transmitted power initial value according to a selected power level.

Abstract: An optical transceiver is disclosed in which the optical output thereof is controlled without degrading the signal quality. The optical transceiver of the invention includes a plurality of transmitter units and a controller that adjusts the bias current of respective transmitter units. The controller, receiving information to decrease/increase the output of the optical transceiver, decides a unique unit that has a largest margin to increase/decrease the bias current and provides a control signal only to the unique unit to increase/decrease the bias current.

Abstract: Described is a method and system for reducing system penalty from polarization mode dispersion. The method includes receiving a plurality of signals at a receiving end of a transmission line, each signal being received on one of a plurality of channels of the transmission line and measuring a signal degradation of at least one of the channels of the transmission line. An amount of adjustment of a polarization controller is determined based on the signal degradation, the amount of adjustment being selected to reduce the polarization mode dispersion. The amount of adjustment is then transmitted to the polarization controller.

Abstract: Optical fiber-based wireless systems and related components and methods are disclosed. The systems support radio frequency (RF) communications with clients over optical fiber, including Radio-over-Fiber (RoF) communications. The systems may be provided as part of an indoor distributed antenna system (IDAS) to provide wireless communication services to clients inside a building or other facility. The communications can be distributed between a head end unit (HEU) that receives carrier signals from one or more service or carrier providers and converts the signals to RoF signals for distribution over optical fibers to end points, which may be remote antenna units (RAUs). In one embodiment, calibration of communication downlinks and communication uplinks is performed to compensate for signal strength losses in the system.

Abstract: The optical transmission equipment includes: a demultiplexer for demultiplexing a transmitted wavelength-multiplexed optical signal to first and second optical signals; a first variable dispersion compensation unit; a second variable dispersion compensation unit; a first error detector; a second error detector; and a dispersion compensation control unit for controlling dispersion compensation amounts of the first and second variable dispersion compensation units based on the detection result of the first or second error detector. Upon detection of a signal error in the first optical signal, the first variable dispersion compensation unit is controlled to change from a first compensation amount to a third compensation amount, and the second variable dispersion compensation unit is controlled to change from a second compensation amount to a fourth compensation amount.

Abstract: A method and system of data transmission; the method comprising: converting data into qubits; transmitting a first qubit; measuring the first qubit at receiver location; determining whether or not to transmit portions of data from a sequential successive qubit based upon the value of the first qubit measured at the receiver location.

Abstract: A system may include a first measurement device configured to be coupled to a first node in an optical path being measured. The first measurement device may be configured to generate a signal at an initiating device; identify an unused channel in an optical path, wherein the optical path includes at least two spans; and transmit the signal on the unused channel. A second test device may be configured to be coupled to a last node in the optical path being measured. The second measurement device may be configured to: receive the signal at a destination device; compensate the signal for chromatic dispersion (CD) and/or polarization mode dispersion (PMD) effects; and determine CD and/or PMD measurements associated with the optical path being measured based on the compensation.

Abstract: A quantum key delivery system includes an optical circulator, an optical low-pass filter, optical splitters, and first and second optical couplers arranged for outputting various wavelength components including correlated-photon pair wavelength components outputted from an optical loop path. The first and second optical couplers output light beams, which are sent over first and second quantum channels to first and second recipients, respectively. Other optical splitters are adapted to output light rays, from which first and second control signals are produced. From auxiliary idler light components transmitted over the first and second quantum channels, clock signals are extracted. The system thus extracts a clock signal for detecting arrival of photons, and stably operates with an expected value of the number of generated correlated photon pairs maintained at a substantially constant value.

Abstract: Consistent with the present disclosure, clock-and-data recovery (CDR) circuitry and driver circuitry are provided on a chip that is separate from the driver circuitry, thereby reducing the amount of power consumed by the driver circuitry and simplifying system design. In one example, timing of the ERZ signals is controlled by a feedback loop that adjusts the phase of a data carrying signal relative to a clock signal, such that the phase has a desired value. Timing of the ERZ signals may thus be adjusted to minimize errors.

Abstract: A network comprising at least one host device having an interface card connected to a backplane of said host device, wherein said interface card comprises at least one cage for receiving a pluggable module which provides at least one embedded communication channel which exchanges performance monitoring data and configuration data between said pluggable module and a far end device.

Abstract: A photonic-cable assembly includes a power source cable connector (“PSCC”) coupled to a power receive cable connector (“PRCC”) via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

Abstract: According to particular embodiments, a signal communicated from a transmitter to a receiver is received. A frequency offset estimate of the signal is determined. The frequency offset estimate indicates a frequency difference between the transmitter and the receiver. The frequency offset estimate is provided as feedback. A next frequency offset is compensated for according to the feedback.

Abstract: A dispersion compensation device includes: an optical branching unit to branch an optical signal to be received; a first dispersion compensator to perform dispersion compensation on one part of the optical signal branched by the optical branching unit with a variable compensation amount; a second dispersion compensator to perform dispersion compensation on another part of the optical signal branched by the optical branching unit; a monitoring unit to monitor the communication quality of an output optical signal of the second dispersion compensator; and a controlling unit to determine the direction of variation in chromatic dispersion of the optical signal based on the direction of variation in communication quality monitored by the monitoring unit and control the compensation amount of the first dispersion compensator based on the result of the determination.

Abstract: A system and method implementing dual stage carrier phase estimation (CPE) in a coherent receiver for an optical fiber communication system. In the first stage, a feed-forward CPE is implemented to make an initial carrier phase estimation of a training sequence. The initial carrier phase estimation is coupled to the second stage which implements a decision-feedback CPE. After a training period, accurate bit decision for system traffic can be achieved using the decision-feedback CPE.

Abstract: A signal detection method used in an optical receiver apparatus detects the variation of an optical input level from the presence or absence of a clock signal and appropriately controls a dispersion compensator, thereby enabling the presence or absence of an input signal to be correctly determined. The signal detection method includes: detecting the level of input light of an optical amplifier, storing the level of the detected input light, comparing the level of the stored previous input light with the level of current input light, detecting the level variation of the input light by the comparison to detect the state change of the presence or absence of an optical signal, performing a dispersion compensation on the input light, and extracting a clock from an optical input. When the level variation of the input light is detected, the presence or absence of the optical signal of the input light is determined from the presence or absence of the clock signal.

Abstract: A digital signal is sent by a one-wire digital input/output unit of a one-wire IR communication system at the side of the dedicated device to an IR transmitting element, a working range is established in which the IR signal is sent, which is received at the side of the target device by an IR receiving element of the one-wire IR communication system of the target device, and the IR signal is sent by the one-wire digital input/out of the IR system across the main communication trunk to the modules of the target device.

Abstract: In-phase signal light and quadrature-phase signal light obtained by mixing input light and local light with each other are converted into digital signals. The quality of a signal to be received is monitored with reference to information obtained through digital signal processing, and the power ratio between the input signal light and the local light that are to be mixed with each other are controlled on the basis of the result of the monitoring.

Abstract: A coherent laser receiver for receiving encoded light which may have propagated over an aberrated path, situated between a source of the encoded light and the coherent receiver. The coherent laser receiver comprises a bundle of optical fibers arranged in an array to receive light, as encoded from a distant optical transmitter or reflective surface, the encoded light from the distant optical transmitter or reflective surface is received by at least a majority of the fibers in the array. A plurality of light amplifiers is provided for amplifying the received encoded light.

Abstract: An optical transmission device for controlling an optical signal output includes a return light detection section for detecting return light of the optical signal transmitted via the optical transmission line; a superimposed light transmission section for generating superimposed light having a superimposed basic low-frequency wave and transmitting the light when return light is detected by the return light detection section; a return light identification section for identifying the return light detected by the return light detection section as Fresnel light caused by a disconnection of the optical connector or Stokes light caused by stimulated Brillouin scattering based on an analysis result of the return superimposed light with respect to the superimposed light transmitted by the superimposed light transmission section.

Abstract: A process and system are disclosed for supplying electrical energy to a device located in a room housing an imaging system (such as an MRI system, for example), wherein the room is shielded from external electromagnetic fields. Certain embodiments of the present invention provide systems and processes for emitting electromagnetic radiation in the wavelength range of the light spectrum from at least one light emission device. Embodiments of the present invention further provide a process and system for transforming the electromagnetic radiation into electrical energy using at least one transducer device located in the room, and supplying the electrical energy to the device so as to minimize interfering electromagnetic fields within the room.

Abstract: A photonic system and method are provided. The system includes an optical source configured to generate a carrier signal; and a modulator configured to modulate the carrier signal with a radio frequency, (“RF”) input signal to generate a modulated signal. The system also includes an optical filter configured to filter the modulated signal to generate a vestigial sideband modulated signal; and an optical detector configured to demodulate the vestigial sideband signal to generate an RF output signal. The system further includes a wavelength controller module configured to set an operating parameter of the optical source.

Abstract: An electronic device includes a casing having a laser light reception region on its outer surface, a receiver that receives transmission data from a partner device, and a suppression member that suppresses leakage of the laser light between the partner device and the electronic device. The partner device includes a laser light emission component and a laser light modulator. The receiver detects, in a state where the partner device and the electronic device are positioned in to communicable positions where the laser light from the partner device is made incident inside the light reception region of the electronic device, the laser light incident inside the light reception region and demodulates the transmission data from the laser light detection result. The suppression member is disposed in at least an area surrounding the light reception region.

Abstract: An optical network device of a passive optical network is introduced. The optical network device includes a light source, a control unit, and a variable optical attenuator. The light source can generate an optical signal. The control unit can generate a magnetic signal based on a control signal capable of providing information relating to a distance between the optical network device and an optical line termination. The variable optical attenuator can adjust a polarization angle of the optical signal based on the magnetic signal.

Abstract: In a polarization multiplexed optical transmitting and receiving apparatus, output light from a light source section of a transmission unit is separated in a polarization separating section, and then modulated in first and second modulation sections, and the modulated lights are synthesized in a polarization synthesizing section, and transmitted to an optical transmission line. Then the polarization multiplexed light propagated through the optical transmission line is demodulated in a reception section of a reception unit, and together with this, transmission characteristic information of the reception light is transferred to the transmission unit. The transmission unit that receives the transmission characteristics information controls a delay section that adjusts a delay amount of relative phases of drive signals of the modulation sections, so that the transmission characteristics of the polarization multiplexed light are within an allowable range.

Abstract: An optical communication system comprising a transmitter including a data register having a plurality of outputs, each output comprising a separate data channel, a plurality of signal processors, each signal processor corresponding to a data, a plurality of laser modules, each laser module coupled to an output of a corresponding signal processor, wherein each laser module modulates the modified signal from its corresponding data channel onto an optical carrier having a selected wavelength, and an optical multiplexer coupled to an output of all the laser modules.

Abstract: In an optical receiving apparatus for receiving an optical DQPSK signal, a phase difference between both arms of an optical interferometer is controlled to an optimum value. The optical DQPSK signal is incident on two optical interferometers in each which a delay-time difference between two arms is set to be equal to a 1-symbol time of the optical DQPSK signal and which are orthogonal to each other. The optical receiving apparatus converts the optical DQPSK signal into an intensity signal and receives it. A differential amplifier obtains a difference signal between outputs of a pre-amplifier and a discriminator connected thereto. The difference signal includes, as an amplitude, a phase shift in a phase section. A control circuit adjusts the phase of the phase section in the optical interferometers to reduce this difference signal, and changes the phase difference between the two arms to a desired phase difference.

Abstract: An apparatus for measuring an OSNR for a communication channel in a WDM optical communications system includes a signal control unit, a receiving unit, and a measuring unit. The signal control unit controls spectral width reduction for an optical signal sent through a target channel. The receiving unit receives spectral data measured from the optical signal received by the target channel under control of the control unit. The measuring unit, based on the spectral data received by the receiving unit, measures the OSNR of the target channel.

Abstract: A burst-mode differential phase shift keying (DPSK) communications system according to an embodiment of the present invention enables practical, power-efficient, multi-rate communications between an optical transmitter and receiver. An embodiment of the system utilizes a single interferometer in the receiver with a relative path delay that is matched to the DPSK symbol rate of the link. DPSK symbols are transmitted in bursts, and the data rate may be varied by changing the ratio of the burst-on time to the burst-off time. This approach offers a number of advantages over conventional DPSK implementations, including near-optimum photon efficiency over a wide range of data rates, simplified multi-rate transceiver implementation, and relaxed transmit laser line-width requirements at low data rates.

Abstract: An optical transceiver and a method to setup the optical transceiver are disclosed, where the transceiver has a function to compensate the distortion and the dispersion due to the limited bandwidth of the electrical signal line, that of the active devices, and that of the optical fiber. The optical transceiver comprises a transmitter with an equalizer unit and a receiver also with an equalizer unit. The equalizer unit in the transmitter compensates the distortion due to the limited bandwidth of the transmission lines for the electrical signal and that of the semiconductor active device, while, the equalizer unit in the receiver compensates the dispersion due to the limited bandwidth of the optical fiber.

Abstract: A small form factor pluggable (SFP) device includes a controller for receiving a first input signal. An optical loopback circuit is coupled to the controller for feeding back a loopback signal to the controller. The loopback signal is generated from the first input signal. An indicator is coupled to the controller for indicating a operational status of the device.

Abstract: A coherent optical communication device includes a demodulator configured to demodulate a reception signal; a local oscillator light optical source configured to generate local oscillator light used for demodulating the reception signal; a memory configured to store wavelength information; and a controller configured to control the local oscillator light optical source when the demodulator cannot receive the reception signal, so that a wavelength of the local oscillator light generated in the local oscillator light optical source is changed to a wavelength specified by the wavelength information stored in the memory.

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: Among others, RF receivers based on whispering gallery mode resonators are described. In one aspect, a photonic RF device includes a laser that is tunable in response to a control signal and produces a laser beam at a laser frequency. The RF device includes a first optical resonator structured to support a whispering gallery mode circulating in the first optical resonator, the optical resonator being optically coupled to the laser to receive a portion of the laser beam into the optical resonator in the whispering gallery mode and to feed laser light in the whispering gallery mode in the optical resonator back to the laser to stabilize the laser frequency at a frequency of the whispering gallery mode and to reduce a linewidth of the laser. The RF device includes a second optical resonator made of an electro-optic material to support a whispering gallery mode circulating in the optical resonator.

Abstract: An optical receiver is described. This optical receiver includes a digital feedback circuit that biases a front-end circuit, which receives an optical signal, so that an analog electrical signal output by the front-end circuit is calibrated relative to a reference voltage corresponding to a decision threshold of a digital slicer in the optical receiver. In particular, during a calibration mode the feedback circuit may determine and store a calibration value that calibrates the analog electrical signal relative to the reference voltage. Then, during a normal operating mode, the feedback circuit may output a current corresponding to the stored calibration value that specifies a bias point of the front-end circuit.

Abstract: Systems and methods for monitoring a data transmission link, especially an optical, bidirectional data transmission link, in which a digital transmit signal is transmitted on a first transmission path from a local end of the data transmission link toward a remote end of the data transmission link. A portion of the power of the transmit signal sent at the local end is transmitted, delayed by a non-zero delay time on a second transmission path as a control signal toward the remote end of the data transmission link. Both signals are received at the remote end and are tested for the presence of events of a predetermined type. A conclusion can be reached on the quality of the transmission link as a function of a time correlation and frequency of the appearance of events in the received transmit signal and in the received control signal.

Abstract: A optical link for achieving electrical isolation between a controller and a memory device is disclosed. The optical link increases the noise immunity of electrical interconnections, and allows the memory device to be placed a greater distance from the processor than is conventional without power-consuming I/O buffers.

Abstract: In an optical waveform measurement system, a phase comparator compares phases between an electric signal output from a PD and an electric signal output from a mixer, and outputs a signal having an amplitude proportional to the phase difference of the two electric signals to a VCO via an LPF, as an error signal. A BPF removes a jitter from the electric signal output from the VCO, and a sampling pulse light source outputs sampling light based on the electric signal with the jitter removed. An optical sampling gate samples signal light to be measured with sampling light output from a sampling pulse light source, and the sampled signal light to be measured is measured by an oscilloscope.

Abstract: Described is a method and system for reducing system penalty from polarization mode dispersion. The method includes receiving a plurality of signals at a receiving end of a transmission line, each signal being received on one of a plurality of channels of the transmission line and measuring a signal degradation of at least one of the channels of the transmission line. An amount of adjustment of a polarization controller is determined based on the signal degradation, the amount of adjustment being selected to reduce the polarization mode dispersion. The amount of adjustment is then transmitted to the polarization controller.

Abstract: Systems and methods for validating a data link between two communication modules, such as optical transceiver modules configured for bidirectional optical communication, are disclosed. In one embodiment a method according to the invention includes a first optical transceiver module transmitting a first validation optical signal to a second optical transceiver module via an optical waveguide, such as an optical fiber, that physically interconnects both transceivers. The first validation optical signal is received by the second optical transceiver module, which lights an indicator light on its housing and returns a second validation optical signal to the first optical transceiver module. Upon receipt of the signal, the first transceiver lights its indicator light and enables data transfer to occur between both transceivers.

Abstract: Out-of-band data communication of diagnostic and/or configuration data is performed using transceivers in a data or communication network. A light beam or other carrier is modulated with high-speed data and out-of-band diagnostic and/or configuration data to create a double modulated data signal. A physical layer signal is created that includes modulations of the double modulated signal. The physical layer signal is transmitted onto a physical link. The diagnostic and/or configuration data can be transmitted in the out-of-band signal without substantially reducing or otherwise interfering with the transmission rate of the high-speed data.

Abstract: Nonlinearity-induced signal distortions are compensated by processing an input communications signal, in the electrical domain prior to Electrical-to-optical conversion and transmission through an optical link of a communications system. According to the invention, a compensation operator is determined that substantially mitigates the nonlinearity-induced signal distortions imparted to an optical signal traversing the communications system. The input communications signal is then input to the compensation operator to generate a predistorted electrical signal. This predistorted electrical signal is then used to modulate an optical source to generate a corresponding predistorted optical signal for transmission through the optical communications system. With this arrangement, arbitrary nonlinearity-induced signal distortions imparted by the optical link can be compensated in such a manner that a comparatively undistorted optical signal is obtained at the receiving end of the optical link.