Abstract: The invention relates to devices and methods of characterising a single unknown pulse signal. They create multiple replica of the original that may be more reliably measured, by dividing the signal through nodes and using different signal pathways that may apply a temporal delay. The device and methods have multiple fields of application, most notably with the internal confinement fusion industry.

Abstract: One embodiment can provide an optical transceiver based on silicon photonics. The optical transceiver can include an optical transmitter and an optical receiver. The optical transmitter or the optical receiver can include one or more semiconductor optical amplifiers (SOAs) configured to amplify optical signals to be transmitted by the optical transmitter or optical signals received by the optical receiver, respectively, thereby facilitating the optical transceiver to meet an optical power budget requirement of a high-speed optical link.

Abstract: In some embodiments, an apparatus includes an optical transceiver that includes a first set of electrical transmitters operatively coupled to a switch. Each electrical transmitter from the first set of electrical transmitters is configured to transmit an electrical signal from a set of electrical signals. In such embodiments, the switch is configured to switch an electrical signal from the set of electrical signals such that the set of electrical signals are transmitted via a second set of electrical transmitters. Each electrical transmitter from the second set of electrical transmitters is operatively coupled to an optical transmitter from a set of optical transmitters. The set of optical transmitters is operatively coupled to an optical multiplexer. In such embodiments, at least one electrical transmitter from the second set of electrical transmitters is associated with a failure within the optical transceiver.

Abstract: In some embodiments, an apparatus includes an optical transceiver that includes a first set of electrical transmitters operatively coupled to a switch. Each electrical transmitter from the first set of electrical transmitters is configured to transmit an electrical signal from a set of electrical signals. In such embodiments, the switch is configured to switch an electrical signal from the set of electrical signals such that the set of electrical signals are transmitted via a second set of electrical transmitters. Each electrical transmitter from the second set of electrical transmitters is operatively coupled to an optical transmitter from a set of optical transmitters. The set of optical transmitters is operatively coupled to an optical multiplexer. In such embodiments, at least one electrical transmitter from the second set of electrical transmitters is associated with a failure within the optical transceiver.

Abstract: A light emitter and methods of constructing the same is disclosed. The light emitter is disclosed as including a jumper chip and one or more light sources, such as Light Emitting Diodes (LEDs). The light sources are connected to the jumper chip via conductive traces manufactured with semiconductor processing techniques. The jumper chip is disclosed as having a plurality of isolated conductive vias, thereby allowing the jumper chip to present multiple different bonding areas that are electrically isolated from one another.

Abstract: This invention concerns real-time multi-impairment signal performance monitoring. In particular it concerns an optical device, for instance a monolithic integrated photonics chip, comprising a waveguide having an input region to receive a signal for characterization, and a narrow band CW laser signal. A non-linear waveguide region to mix the two received signals. More than one output region, each equipped with bandpass filters that extract respective discrete frequency bands of the RF spectrum of the mixed signals. And, also comprising (slow) power detectors to output the extracted discrete frequency banded signals.

Abstract: Systems and methods are disclosed to provide an upstream rate between 1 Gbps and 10 Gbps in a cost effective manner in a 10 GEPON. In an embodiment, an optical network unit (ONU) transmitter includes a burst transceiver and a physical layer (PHY) including a high performance digital to analog converter (DAC), a pulse amplitude modulation (PAM) module configured to encode end user data using a modulation scheme having more than two levels, and a laser. The ONU transmitter transmits the encoded end user data to an optical line terminal (OLT) receiver, which demodulates the data using a PAM demodulator and sends it to a service provider.

Abstract: It is aimed to provide a phase modulation apparatus that realizes high-precision phase modulation in high-speed phase modulation of dual optical pulses. A phase modulator 105 included in the phase modulation apparatus, when a dual optical pulse with a time difference composed of a signal optical pulse SP and a reference optical pulse RP passes therethrough, phase-modulates this dual optical pulse in proportion to an applied voltage of an electrical pulse. As a result, a phase-modulated SP? and a phase-modulated RP? are output. A modulation signal generator 106 outputs an electrical pulse of a predetermined bias at an input timing of a trigger signal, according to an input of a four-valued data signal, for example. The modulation signal generator 106 outputs, for one input of the trigger signal, a dual electrical pulse having a time difference and having opposite polarities.

Abstract: An optical modulator includes a light input/output unit receiving an incident optical signal which has not been modulated, splitting the incident optical signal into a first optical signal and a second optical signal, and transmitting the first and second optical signals to a first path and a second path, respectively, of an optical waveguide. A phase shifter is positioned in at least one of the first and second paths and modulates a phase of at least one of the first and second optical signals, which have been received through the first and second paths, respectively, in response to an electrical signal. A phase-modulated signal is output. A reflective grating coupler reflects signals respectively received through the first and second paths back along the first and second paths respectively.

Abstract: Data security of a multi-dimensional code system is increased. An optical device is provided with a single input port; a splitter splitting an input light from the input port into a plurality of lights; a plurality of phase shifters each shifting one of the lights split by the splitter; a multi-port encoder/decoder inputting the lights whose phases are shifted by the phase shifters and generating spectral encoded codes; and a plurality of output ports outputting the spectral encoded codes generated by the multi-port encoder/decoder.

Abstract: Provided is an optical module. The optical module includes: an optical bench having a first trench of a first depth and a second trench of a second depth that is less than the first depth; a lens in the first trench of the optical bench; at least one semiconductor chip in the second trench of the optical bench; and a flexible printed circuit board covering an upper surface of the optical bench except for the first and second trenches, wherein the optical bench is a metal optical bench or a silicon optical bench.

Abstract: In a device and method for the optical transmission of data using a pulse-width-modulated LED (2), a startup phase ascertainment unit (3) for ascertaining at least one startup phase of the LED (2) as a function of a sequence of detected switching states of the LED (2) and a modulation unit (4) for modulating the data to a light signal emitted by the LED (2) during the ascertained startup phase of the LED (2) are provided, and data packets are first deleted from the data packet queue or queues after they have been successfully transmitted.

Abstract: A PPM transmitter includes an optical clock generator for generating equally-spaced optical pulses with a sampling period T; an encoder for transforming an incoming waveform U(t) into a linear combination V(t) of U(t) and a delayed output V(t?kT) according to a rule V(t)=U(t)+aV(t?kT), where k is a positive integer, V(t) is voltage generated by the encoder and a is a coefficient; and an optical delay generator for delaying optical pulses generated by the optical clock generator in proportion to the voltage V(t), such that ?tn=bV(t), where b is another coefficient and where ?tn is the amount of delay imposed by the optical delay generator. The PPM transmitter functions with a PPM receiver for communicating data without the need to transmit or otherwise provide a clock signal. The PPM receiver decodes an original series of the delayed optical pulses Q(t) and a second series Q(t?ckT) delayed by ckT where c is a coefficient.

Abstract: The present invention refers to a method for robust multi-level encoding of optical signals. The method uses a transmitter that transforms electric signals into optical signals and a receiver capable to transform optical signals into electric signals. The transmitter is capable to generate optical pulses having at least two different durations. The amplitudes of the pulses are preferably close to each other. The transmitter is fast, and the receiver is slow such that the response time of the receiver exceeds at least the shortest of the durations of the optical pulses. Then the receiver effectively integrates the optical signal and generates the electric signal having a larger amplitude when the optical signal has a larger duration. Thus, the method converts the modulation in pulse duration into the modulation in signal amplitude. In different embodiments of the present invention, the transmitter can be realized by a light-emitting diode, superluminescent light-emitting diode, or a diode laser.

Abstract: Provided is a multi-value optical transmitter in which a DC bias may be controlled to be stabilized so as to obtain stable optical transmission signal quality in multi-value modulation using a dual-electrode MZ modulator. The multi-value optical transmitter includes: D/A converters for performing D/A conversion on first and second modulation data which are set based on an input data series, so as to generate a first and a second multi-value signal, respectively; a dual-electrode MZ modulator including phase modulators for modulating light from a light source based on the first multi-value signal and the second multi-value signal, so as to combine optical signals from the phase modulators to output the optical multi-value signal; an optical output power monitor for detecting average power of the optical multi-value signal; and a DC bias control unit for controlling a DC bias for the dual-electrode MZ modulator, so as to maximize the average power.

Abstract: A method is described for driving a light source, particularly a HID lamp (2), the method comprising the steps of: providing a commutating DC current for supplying the lamp; and varying a commutation period (T) in order to transmit data. In an embodiment, the duration of each commutation period (T) is set to be equal to one of two possible values (T1, T2) such as to encode a digital bit.

Abstract: The present invention relates to an optical modulating device with frequency multiplying technique for electrical signals, which primary comprises a mixer, which generates a mixed data signal from a first electrical signal and a second electrical signal. The mixed data signal is then received by a first phase shift device to have its phase shifted and becomes a first shifted signal. The first electrical signal is further received by a second phase shift device to have its phase shifted and becomes a second shifted signal. The present invention further comprises an integrated electro-optic modulator (Mach-Zehnder modulator), which is used to receive an input optical signal, the mixed data signal, the first shifted signal, the second shifted signal and the first electrical signal mentioned above, the integrated electro-optic modulator will then modulates the input optical signal into a frequency multiplying output optical signal that carries the first electrical signal and the second electrical signal.

Abstract: In a method for optically transmitting data by means of a pulse-width-modulated light source (LED), a pulse duty factor (N) of a pulse width modulation is specified to set the brightness of the light source (LED). A bright time (T) is divided into at least a first and second partial bright time using at least one blanking so that the data (DATA) to be transmitted are encoded by the start and time length of the at least one blanking. The sum of the partial bright times within the pulse width modulation cycle substantially corresponds to the bright time according to the specified pulse duty factor.

Abstract: It is an object of the present invention to provide a communications system for communication between two remote terminals, where even at very long distances between these two terminals and/or at very small signal-to-noise ratios a robust communication is possible. The invention achieves the goal set before by suggesting an inventive pulse position modulation scheme and a corresponding optical communications system. The system and method according to the invention are very well suited for communication with a satellite in deep space, for instance.

Abstract: Embodiments of the present invention provide a method and apparatus for producing a phase coded non-return-to-zero (PC-NRZ) optical signal. The method includes providing an input optical signal; providing first and second drive signals, the first drive signal having a first data pattern of first and second signal levels, the second drive signal having a second data pattern, the second data pattern having third and fourth signal levels that toggle at least when the first drive signal changes from the first signal level to the second signal level; and modulating amplitude of the input optical signal with the first drive signal and modulating phase of the input optical signal with the second drive signal to produce the PC-NRZ optical signal. A PC-NRZ optical transmitter and an optical transmission system applying the PC-NRZ optical transmitter are also provided.

Abstract: A transmission device that includes: a radio signal transmission processing section that transmits a radio carrier wave overlaid with transmitting information after being modulated by pulse position modulation; an optical signal transmission processing section that transmits an optical carrier wave overlaid with the transmitting information after being modulated by the pulse position modulation; and a baseband processing section that modulates the transmitting information in accordance with the pulse position modulation of shared use with the radio signal transmission processing section and the optical signal transmission processing section.

Abstract: A phase control arrangement has a structure in which a Superstructured fiber Bragg Grating (SSFBG) 40 has fifteen unit Fiber Bragg Gratings (FBGs) arranged in series in a waveguide direction. The SSFBG 40 is fixed to the core of an optical fiber 36 that includes a core 34 and cladding 32. The difference ?n between the maximum and minimum of the effective refractive index of the optical fiber is 6.2×10?5. The phase difference of Bragg reflected light from two unit diffraction gratings that adjoin one another from front to back and provide equal code values is given by 2?M+(?/2), where M is an integer. Further, the phase difference of the Bragg reflected light from two unit diffraction gratings that adjoin one another from front to back and provide different code values is given by 2?M+(2N+1)?+(?/2) where M and N are integers.

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 arrangement for generating beat notes with a relatively high signal-to-noise ratio (SNR) utilizes a pulsed laser source coupled into a section of post-processed highly-nonlinear optical fiber (HNLF) to generate a frequency comb having one or more regions of enhanced spectral power. A second laser signal source is overlapped with the frequency comb to form one or more “beat notes” at difference frequencies(y) between the second source and the continuum comb. By virtue of the post-processing, areas of spectral enhancement are formed along the comb, and are positioned to interact with the second laser signal to generate optical beat notes. The second laser signal may be from an external source (forming beat notes from a signal “outside” of the comb), or may be a frequency-multiplied version of the generated supercontinuum (forming beat notes from a signal “within” the comb).

Abstract: A method and system for storing and transmitting data using variable pulse characteristics to represent ASCII or UNICODE characters, of the value of a string of data using a number base higher than 2. Pulse characteristics are modified to correspond to different data values. Pulse characteristics can include pulse durations, pulse spacings, pulse amplitudes, pulse phases, pulse polarities, pulse shapes and/or other pulse characteristics.

Abstract: A wireless, automatic door obstruction detection system for protecting a motorized door or gate by signaling various hazardous conditions and reacting to said conditions by signaling control means. The invention utilizes wireless infrared emitter, receiver and controller apparatus. Infrared pulse timing data is sent as pulse repetition rate changes depending upon battery condition. In a preferred embodiment of the invention, the photoelectric transmitter emits timed pulse groups to present control information differentiating between a good battery and a low battery condition in the wireless transmitter. A wireless photoelectric transmitter extends the time period between pulse groups to indicate a low battery condition. A low battery condition signaling thereby presents a low power drain condition allowing for an extended period of low battery condition signaling.

Abstract: Embodiments of fiber optic communication systems are disclosed. In one embodiment, the system includes an optical channel having a channel response, a pulse-shaping transmitter coupled to a first end of the optical channel, and a receiver coupled to a second end of the optical channel. The transmitter includes a spread pulse modulator to shape pulses of data prior to transmission and an electrical to optical converter to transmit electrical data signals as the light signals over the optical channel. The receiver includes an optical to electrical converter to receive light signals from the optical channel and generate electrical data signals and a matched filter to receive and filter the electrical data signals with a response substantially matching a combined response of the transmitter and the channel response to increase a signal to noise ratio thereof.

Abstract: The phase modulation in which the frequency chirp becomes 0 at the timing which the user wants to synchronize, and the frequency chirp becomes larger as the time deviates in a positive or negative direction from this timing is applied to the signal light with each wavelength comprising pulse train of different timing. Thus, the optical pulses which deviate from the timing which the user wants to synchronize receive the frequency chirp in accordance with the amount of the timing deviation. The WDM signal light which has been chirped in this way is made to pass a linear dispersive medium, and the dispersion fit for the amount of frequency chirp is made to be given. By adjusting the amount of dispersion, it is possible to obtain the pulses which conform to the timing at which the user wants to synchronize the pulses of each wavelength.

Abstract: An interference-rejection coding method for an optical wireless communication system and such an optical wireless communication system are provided. The coding method uses delay modulation, block code techniques and filtering to reduce the low frequency interference from light sources. A plurality of codewords from the block codes are reserved for performing digital data recovery. The invention removes the need of analog clock data recovery circuit, and does not require complex hardware for realization. Therefore, it can be applied to a wide range of applications, such as optical WLAN, data transmission of medical facilities, wireless communication in the aircraft, encrypted data transmission network, and low-priced transmission interfaces.

Abstract: Before being incident to a nonlinear medium, a short pulse is intensity-modulated with a bit string pattern, and then made incident. When the pulse light corresponding to a bit value ‘0’ is incident to the nonlinear medium, the pulse light is intensity-modulated so that the spectral width thereof is not spread to a predetermined spectral region due to the nonlinear phenomena, thereby producing a light state of being not output from an optical demultiplexer. Meanwhile, when the pulse light corresponding to a bit value ‘1’ is incident to the nonlinear medium, the pulse light is intensity-modulated so that the spectral width thereof is spread to the predetermined spectral region due to the nonlinear phenomena, thereby producing a light state of being output from the optical demultiplexer.

Abstract: An optical transmitter for an optical communication system is provided. Included in the transmitter is a first optical delay element configured to generate a second optical signal from a first optical signal. A second optical delay element is configured to generate a fourth optical signal from a second optical signal. An optical multiplexer is configured to combine the third and fourth optical signals to produce a fifth optical signal. Also included is an optical modulator configured to alter a pulse width of the fifth optical signal to generate a sixth optical signal. An optical delay controller is configured to control the first optical delay element and the second optical delay element based on the sixth optical signal.

Abstract: A data communication system capable of controlling the brightness of light sensed by the human eye and quality communication using an illuminative light is provided. A PWM circuit 11 adjusts pulse width in conformity with a light intensity control signal corresponding to a desired light intensity, resulting in a PWM signal. The PWM signal is then transmitted to a phase inverter 12. The phase inverter 12 outputs the PWM signal as is when a data signal to be transmitted is 0, for example, while it inverts the phase of the PWM signal and then outputs the resulting inverted PWM signal when the data signal is 1. A light source driver circuit 13 drives, a light source 14 such as an LED, organic electroluminescence, or the like in conformity with the phase inverted signal to emit light. In a data reception unit 2, an optical sensor 21 converts light emitted from an illuminating device 1 to an electric signal. A phase detection circuit 22 detects the phase of the signal and then outputs a received data signal.

Abstract: A system and method for increasing transmission distance and/or transmission data rates using tedons and an encoding scheme to reduce the number of ones in a data signal is described. For example, the method for increasing transmission distance and transmission data rate of a fiber optical communications link using tedons includes the steps of encoding a data signal to be transmitted using an encoding scheme that reduces a number of ones in the data signal, transmitting the encoded data signal over the fiber optical communications link, receiving the encoded data signal and decoding the encoded data signal.

Abstract: System and method for transmitting and receiving encoded signals over a network along with one or more additional signals transported within a spectral gap created by the coded signals.

Abstract: A method and system is disclosed for making timing alignment for a data transmission system, the method comprising providing a reference clock signal with a first frequency to a multiplexer through a phase shifter, generating a multiplexed signal with a second frequency by the multiplexer, wherein the second frequency follows the first frequency and is higher than the first frequency by a predetermined proportion, sending the multiplexed signal to a modulator, and phase shifting the reference clock signal by the phase shifter before the reference clock signal is provided to the multiplexer, wherein a timing of the multiplexed signal at the second frequency level can be adjusted by adjusting a timing of the reference clock signal at the lower first frequency level.

Abstract: Systems and methods are described for pulse communications using precision timing. A method includes digitally pulse coding a data stream; and modulating a carrier signal using the digitally pulse coded data stream.

Abstract: A light emitting diode driving device for driving an LED includes (i) a driving pulse current generating circuit for generating a driving current for the LED in accordance with a driving pulse signal supplied from outside and (ii) a differentiating circuit for generating a peaking current obtained by differentiating the driving pulse signal. A current that is equal to the sum of the driving current and the peaking current flows to the LED. The light emitting diode driving device further includes a peaking control circuit for controlling the magnitude of the peaking current generated from the differentiating circuit.

Abstract: An optical transmission system which provides bandwidth restricted optical signal comprises an input terminal (10) for accepting an electrical binary signal, an amplifier (12) for amplifying said electrical binary signal to the level requested for operating an electrical-optical converter (16) such as a Mach Zehnder light modulator, a bandwidth restriction means (14) which is for instance a low pass filter for restricting bandwidth of said electrical binary signal, and an electrical-optical conversion means (16) such as a Mach Zehnder light modulator for converting electrical signal to optical signal. Because of the location of the low pass filter (14) between an output of the amplifier (12) and the Mach Zehnder light modulator (16), the amplifier (12) may operate in saturation region to provide high level output signal enough for operating the Mach Zehnder light modulator, and a signal shaped by the low pass filter (14) is applied to the Mach Zehnder light modulator (16) with excellent waveform.

Abstract: A PPM transmitter includes an optical clock generator for generating equally-spaced optical pulses with a sampling period T; an encoder for transforming an incoming waveform U(t) into a linear combination V(t) of U(t) and a delayed output V(t?kT) according to a rule V(t)=a(U(t)+V(t?kT)), where k is a positive integer, V(t) is voltage generated by the encoder and a is a coefficient; and an optical delay generator for delaying optical pulses generated by the optical clock generator in proportion to the voltage V(t), such that ?tn=bV(t), where b is another coefficient and where ?tn is the amount of delay imposed by the optical delay generator. The PPM transmitter functions with a PPM receiver for communicating data without the need to transmit or otherwise provide a clock signal.

Abstract: A miniature waveform modulator is provided to modulate an infrared laser. The miniature waveform modulator outputs a pulse train having different and specified pulse widths, with the pulse train used to modulate the laser. In one embodiment, the pulse train extends over a significant period of time without resorting to generating short pulse trains and combining them. The subject architecture permits the miniature waveform modulator to be compact and implementable on an electronic circuit card. It is significant that the pulse train is generated without software intervention by automatically copying a timing table to a buffer that is automatically read out to a pulse generator. If the buffer size is smaller than that required by the timing table, slices or segments of the timing table are sequentially read out or copied to the buffer, with the next timing table segment transferred to the buffer upon read out of a prior segment.

Abstract: In an LSI system, a short optical pulse train is guided to an optical divider which divides the short optical pulse train into first and second short optical pulse trains. A retardation of ½ of the pulse period is produced between the first and second short optical pulse trains. The first and second short optical pulse trains are guided to first and second photodiodes on an LSI chip and are converted in the first and second electric current pulse trains, respectively. The first and second electric current pulse trains are supplied to an electrical clock output terminal electrically connected to the first and second photodiodes so that the electrical clock output terminals generates an electric clock pulse.

Abstract: A system for generating a return-to-zero differentially-phase-shift-keyed (RZ-DPSK) optical signal comprising: a driver comprising an N-level digital multilevel transformer (DMT) configured to receive a two level digital electrical signal representing 1s and 0s and output a N-level electrical signal, wherein N>2; an FM source configured to receive the N-level electrical signal output by the driver and generate an optical frequency modulated signal; and an optical spectrum reshaper (OSR) configured to receive the optical frequency modulated signal output by the FM source and generate the desired RZ-DPSK optical signal.

Abstract: A method and system is disclosed for making time alignment for a data transmission system. A first reference clock signal is provided to a first multiplexer coupled to a data modulator through a data driver, and a second reference clock signal is provided to a second multiplexer coupled to a clock modulator through a clock driver. Phase adjustment of the reference clock signal are conducted before the first reference clock signal is provided to the first multiplexer, wherein the phase adjustment aligns a timing of data modulated by the data modulator with a periodically modulated light source generated by the clock modulator.

Abstract: Methods of providing duplex free-space optical, communication comprising receiving a time-shift keying (TSK) encoded signal and selectively re-modulating—and optionally retro-reflecting—received TSK pulses so as to transmit an on-off keying (OOK) signal. Related apparatus and signals are also provided.

Abstract: An all-optical PPM modulator comprises one or more sources of trains of optical control pulses and optical signal pulses, the optical control and optical signal pulses being equally spaced, but differentiated from one another by at least having different optical wavelengths and/or polarizations prior to modulation. An electro-optic modulator, for example, amplitude modulates the control pulses using a signal. A chirped Bragg reflector in an non-linear waveguide receives both the amplitude modulated optical control signal pulses and unmodulated optical signal pulses at an entrance port thereof, the waveguide having a path length selected to achieve temporal overlap of the control and signal pulses in the waveguide. The chirped Bragg reflector is resonant to the optical signal pulses and off-resonant to the optical control pulse.

Abstract: A transmitter formed of two or more light-emitting sections such as LEDs, which are physically arranged in a predetermined manner, is disposed in the real world object, and each light-emitting section transmits data by flashing at a flashing pattern representing the transmission data of a predetermined bit length. A receiver, on the other hand, includes a photoreceiving section formed from a two-dimensional photoreceiving surface, decodes the transmission data on the basis of the photoreceived flashing pattern, and recognizes the spatial information of an object on the basis of the flashing position on the two-dimensional photoreceiving surface. Therefore, information, such as an ID, can be obtained from the object in the real world, and also, the spatial position of the object can be recognized at the same time.

Abstract: One embodiment of the invention relates to producing optical pulses for use on a transmission link. A light source is configured to produce an optical signal. A pulse generator is coupled to the light source. The pulse generator is configured to receive, for a first channel, the optical signal and a clock signal. The pulse generator is also configured to modify the optical signal based on the clock signal to produce an optical pulse having a predetermined pulse shape. The clock signal is associated with the predetermined pulse shape.

Abstract: An optical transceiver for converting and coupling an information-containing electrical signal with an optical including a housing having an electrical connector with a plurality of XFI electrical interfaces for coupling with an external electrical cable or information system device and for transmitting and/or receiving an information-containing electrical signal having a data rate ate least 10 Gigabits per second on each interface, and a fiber optic connector adapted for coupling with an external optical fiber for transmitting and/or receiving an optical communications signal having a data rate at least 40 Gigabits per second; and at least one electro-optical subassembly in the housing for converting between and information-containing electrical signal and a modulated optical signal corresponding to the electrical signals.

Abstract: An optical RZ transmitter comprises an optical signal source and a pair of electro-optical modulators in tandem, one arranged to receive a NRZ electrical data signal and the other a clock signal at the data rate of the data signal. The phase difference between the data signal and the clock signal is controlled by adding a first dither signal to a bias signal applied to the modulator receiving the data signal, and a second dither signal, having a different frequency, to the phase difference. The amplitude of variations in the power of the optical output signal corresponding to cross-modulation of the first and second dither signals is detected and the phase difference is controlled in response to the detected amplitude.

Abstract: A method for transmitting digital data includes splitting a coherent optical carrier having a subcarrier into mutually coherent optical carriers, producing corresponding sequences of phase shifts in each of the mutually coherent optical carriers, and then, interfering the mutually coherent optical carriers. The interfering produces an output optical carrier whose subcarrier has modulated inphase and quadrature components with a corresponding sequence of pairs of values. The pairs of values of the modulated inphase and quadrature phase components produced by the interfering correspond to a sequence of coordinate pairs for the signal points the 4-PSK 2D, 16-QAM 2D, or 16-PSK 2D constellation.