Class / Patent application number | Description | Number of patent applications / Date published |
398185000 | Hybrid modulation | 30 |
20080219677 | OPTICAL TRANSMITTER - An optical transmitter for carrying out an optical modulation based on a data signal to be transmitted, thereby generating a transmission light signal, includes an optical phase modulating section for carrying out an optical phase modulation over an output light of a light source based on a data signal, an optical pulse modulating section for carrying out an optical pulse modulation over an output light of the optical phase modulating section based on a clock signal and outputting the light as an optical transmission output, an extending section for extending a code transition time of the data signal and applying the data signal to the optical phase modulating section, and a phase control section for modulating a phase shift amount of the data signal or the clock signal with a dither signal and carrying out a synchronous detection over the optical transmission output, and controlling the phase shift amount with a synchronous detection signal. | 09-11-2008 |
20090060526 | OPTICAL FM SOURCE BASED ON INTRA-CAVITY PHASE AND AMPLITUDE MODULATION IN LASERS - An optical transmitter is discloses having a gain section and a phase section. The phase section is modulated to generate a frequency modulated signal encoding data. The frequency modulated signal is transmitted through an optical spectrum reshaper operable to convert it into a frequency and amplitude modulated signal. In some embodiments, a driving circuit is coupled to the phase and gain sections is configured to simultaneously modulate both the phase and gain sections such that the first signal is both frequency and amplitude modulated. | 03-05-2009 |
20090074425 | OPTICAL TRANSMITTER AND CONTROL METHOD THEREOF - An optical transmitter which modulates the phases and intensities of double pulses and then transmits them, includes a branching section which branches each of the input double pulses to first and second paths, a first optical modulator placed in the first path, second and third optical modulators placed in series in the second path, and a combining section which combines the double pulses having traveled through the first path with the double pulses having traveled through the second path to output double pulses. A control section controls such that each of the first and second optical modulators performs any one of relative intensity modulation and relative phase modulation on the double pulses passing through, and the third optical modulator performs relative phase modulation on the double pulses passing through. | 03-19-2009 |
20090092401 | Quaternary phase modulator - In a quaternary phase modulator including two phase modulators disposed in parallel and a phase adjuster that adjusts a phase difference when the outputs of the two phase modulators are combined, there are provided a second light source that introduces light propagated in a backward direction, a first controller that controls the bias of the two phase modulators so that the intensity of the backward light is a minimum on the input side of the quaternary phase modulator, and a second controller that controls the bias of the phase adjuster so that a result monitored by a photodiode having a bandwidth not exceeding the bit rate on the output side of the quaternary phase modulator is a minimum, the first controller being implemented after the second controller is implemented. | 04-09-2009 |
20090110408 | Laser Optical Transmission System with Dual Modulation - An optical transmitter for generating a modulated optical signal for transmission over dispersive fiber optic links in which a first information-containing radio frequency signal input is applied to a modulation circuit for directly modulating a semiconductor laser with the signal input. The output of the laser is applied to a phase modulator to which a second information-containing radio frequency signal is applied. | 04-30-2009 |
20090162076 | METHOD AND SYSTEM FOR ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY - A method and system of measuring the spectroscopic impedance of a sensor and its immediate surroundings. The sensor is disposed on an engineered structure and is coated with a protective coating. The method includes providing a first optical signal having a first modulation frequency and amplitude. The method also includes transmitting the first optical signal and a second optical signal from a first location to a sensor location. The method also includes modulating the second optical signal with a second modulation frequency and amplitude, the second modulation frequency and amplitude converted from the first optical signal. The method also includes comparing the first modulation frequency to the second modulation frequency to determine one of a phase difference and a time lag and calculating the electrochemical impedance spectroscopy of the sensor and its immediate surroundings as a function of frequency. | 06-25-2009 |
20090252501 | Device and method for transmitting optical data signals - Disclosed are a device and a method for transmitting an optical data signal over an optical transmission channel, comprising a differential phase shift keying unit for differential phase shift keying of at least one serial data stream to generate a differential phase shift keying coded data stream; an amplitude shift keying unit for amplitude coding of at least two further serial data streams that can be selectively activated to generate an amplitude shift keying coded data stream; and a modulation unit for generating an optical data signal in accordance with a control signal that is, formed from the generated differential phase shift keying coded data stream and from the generated amplitude shift keying coded data stream. | 10-08-2009 |
20090324253 | OPTICAL MODULATOR FOR HIGHER-ORDER MODULATION - According to one embodiment of the invention, a 16-QAM optical modulator has a Mach-Zehnder modulator (MZM) coupled to a drive circuit that drives the MZM based on two electrical binary signals. The output of the MZM corresponds to an intermediary constellation consisting of four constellation points arranged on a straight line in the corresponding in-phase/quadrature-phase (I-Q) plane. Two of these constellation points correspond to a zero phase, and the remaining two constellation points correspond to a phase of π radian. The 16-QAM optical modulator further has a phase shifter that modulates the output of the MZM based on two additional electrical binary signals. The resulting optical output signal corresponds to a star 16-QAM constellation, which is produced by incremental rotation of the intermediary constellation. | 12-31-2009 |
20100008679 | Phase Shift Keyed Modulation of Optical Signal Using Chirp Managed Laser - A high-speed optical transmitter comprises multiple digital lanes that are provided to a bank of digital-to-analog converters. The analog signals are then used to Phase Shift Keyed (PSK) modulation using a Chirp Managed Laser (CML)-based transmitter, and potentially using dual polarization. A corresponding optical receiver receives the sequence of optical signals at a demodulator. For each polarization, the demodulator includes a corresponding demodulation channel that is configured to demodulate that polarization component of the optical signal into one or more signal components. Each of these signal components is converted into a corresponding digital signal using a corresponding analog-to-digital converter. In the case of higher-order PSK modulation (e.g., 8PSK or higher), for each polarization, the analog converter has a lower sampling rate than for QPSK modulation. | 01-14-2010 |
20100054756 | Optical modulator and optical transmitter using the same - In an optical modulator, a DQPSK modulating section, a waveguide optical amplifying section, and an RZ modulating section are cascade connected on an optical path between input and output ports, and power of RZ-DQPSK signal light output from the output port is monitored by a photodetector, to feed-back control the waveguide optical amplifying section by an output control section so that the monitored power becomes constant at a target level. As a result, a small and low-cost optical modulator that can reliably compensate respective losses in a phase modulating section and an intensity modulating section, and differences of the respective losses, can be realized. | 03-04-2010 |
20100202785 | QUADRATURE AMPLITUDE MODULATION SIGNAL GENERATING DEVICE - A quadrature amplitude modulation (QAM) signal generator, which can obtain optical signals such as QAM signals without handling multilevel electrical signals, can be produced by using a plurality of parallel Mach-Zehnder modulators (MZMs), such as quadruplex parallel MZMs (QPMZM). The quadrature amplitude modulation (QAM) signal generator includes a first waveguide, a first quadrature phase-shift-keying (QPSK) signal generator provided on the first waveguide, a second waveguide connected with the first waveguide at a wave-combining point, and a second quadrature phase-shift-keying (QPSK) signal generator provided on the second waveguide. | 08-12-2010 |
20100232807 | System And Method For Shaping A Waveform - An optical transmission system for transmitting an optical pulse in a dielectric waveguide, the system including a filter for altering a shape of the optical pulse in both amplitude and phase with respect to time so as to substantially suppress the generation of third-order nonlinearities and increase a power level of the optical pulse, the filter further providing a secure encrypted optical waveform that may be decrypted by a matching optical filter, the system allowing for energy sharing of the pulses to substantially increase system bandwidth. | 09-16-2010 |
20100303470 | OPTICAL TRANSMITTER - An optical transmitter includes an optical modulator including a phase modulator, and a delay interferometer to delay and interfere a part of an optical output of the optical modulator, and a controller to control an amplitude of a driving DPSK modulation signal to be supplied to the optical modulator based on a result derived from a level of an output signal of the delay interferometer. | 12-02-2010 |
20110170876 | SYSTEM AND METHOD FOR TRANSMITTING SIGNALS - A signal-transmitting system includes a digital-to-analog converter, an optical modulator, first and second electrodes, an optical phase shifter, and an optical coupler. The digital-to-analog converter converts digital data into an electrical analog signal. The optical modulator includes a first optical waveguide configured to transmit a first optical carrier, a second optical waveguide configured to transmit a second optical carrier, a first electrode positioned on the first optical waveguide, and a second electrode positioned on the second optical waveguide. The first and second electrical couplers are configured to couple respective electrical analog signals and electrical carriers to electrodes to generate modulation waves. The modulation waves are different in phase. The optical phase shifter is configured to shift the second modulation wave by a predetermined phase, and the optical coupler is configured to couple the first and second modulation waves to generate an optical output signal. | 07-14-2011 |
20110170877 | OPTICAL TRANSMITTER APPARATUS - An optical DQPSK modulator comprises a pair of phase modulators. Each of the pair of the phase modulators is provided with first and second driving signals. The first and second driving signals are amplified by first and second amplifiers, respectively. An RZ intensity modulator generates an optical RZ-DQPSK signal from an optical DQPSK signal output from the optical DQPSK modulator. A photodetector generates a monitor signal from the optical RZ-DQPSK signal. A gain adjuster unit adjusts the gains of the first and second amplifiers so as to minimize the power of the monitor signal. | 07-14-2011 |
20120106980 | CONTROLLED DEPOLARIZATION USING CHIRP FOR MITIGATION OF NONLINEAR POLARIZATION SCATTERING - A coherent optical transmitter circuit is disclosed in which controlled chirp is employed, enabling the suppression of nonlinear polarization scattering in dual polarization coherent systems, such as those which employ dual polarization-quadrature phase-shift keying (DP-QPSK). By separately chirping the modulated signals of each polarization tributary signal, the polarization state of the output DP-QPSK signal varies during a time period corresponding to a symbol bit period. Such controlled variations in the output DP-QPSK signal result in the mitigation of nonlinear effects associated with the network infrastructure over which the signal is transmitted, resulting in enhanced system performance. Enhanced system performance, for example, can be seen in greater reach and improved signal quality of the transmitted signal. | 05-03-2012 |
20120163831 | DIGITAL MODULATION METHOD AND DEVICE, ESPECIALLY AN OPTICAL DIGITAL MODULATION METHOD AND DEVICE - A modulation method, especially an optical modulation method, using the principle of discrete IQ modulation. The modulation method includes generating a carrier signal (S | 06-28-2012 |
20120321323 | Variable Line-Rate Optical Transmitter by Modulation Format Hopping Using Electrical-Optical-Electrical EOE Generated QAM Signal - The present method is for generating a 4-level optical signal and it includes providing a continuous wave CW optical source; modulating the CW optical source with a first intensity modulator driven by a binary electrical signal a n Gbits/s to generate an optical signal; employing a second intensity modulator as a pulse carving modulator that is driven by an RF signal at n GHz thereby generating a 4 level optical signal for subsequent detection by a receiver. | 12-20-2012 |
20130148981 | OPTICAL TRANSMITTER - After a startup of an optical transmitter, a control is started in such a way that a modulation amplitude of a driving signal of a phase modulator is set as 0, and that an operational point of a bias voltage is set as the lowest point of light transmission characteristics of the phase modulator. When the operational point of the bias voltage reaches the lowest point, the modulation amplitude of the driving signal is gradually increased from 0 to 2Vπ. | 06-13-2013 |
20130148982 | CHIP-BASED ADVANCED MODULATION FORMAT TRANSMITTER - In various embodiments, a monolithic integrated transmitter, comprising an on-chip laser source and a modulator structure capable of generating advanced modulation format signals based on amplitude and phase modulation are described. | 06-13-2013 |
20140219663 | METHODS AND ARRANGEMENTS FOR FREQUENCY SHIFT COMMUNICATIONS - Embodiments relate to communicating data by varying a frequency of an amplitude modulated light source. Embodiments may comprise logic such as hardware and/or code to vary a frequency of an amplitude-modulated electromagnetic radiator such as a visible light source, an infrared light source, or an ultraviolet light source. For instance, a visible light source such as a light emitting diode (LED) may provide light for a room in a commercial or residential building. The LED may be amplitude modulated by imposing a duty cycle that turns the LED on and off. In some embodiments, the LED may be amplitude modulated to offer the ability to adjust the intensity of the light emitted from the LED. Embodiments may receive a data signal and adjust the frequency of the light emitted from the LED to communicate the data signal via the light. In many embodiments, the data signal may be communicated via the light source at frequencies that are not perceivable via a human eye. | 08-07-2014 |
20140255045 | EXTERNALLY MODULATED OPTICAL TRANSMITTER WITH CHIRP CONTROL - An optical transmitter includes a laser and an external modulator that is used to modulate the optical signal using amplitude modulation (AM). The AM is accompanied by frequency modulation (FM) of the output signal that is generally detrimental to system performance. Both the laser and the modulator are driven by an RF input signal, where part of this RF signal is common. By adjusting the relative drive signals the FM response to the modulator drive signal can be cancelled by a laser drive signal or adjusted to a preferred value. | 09-11-2014 |
20140321863 | MULTIPLE LEVEL SIGNALING FOR PASSIVE OPTICAL NETWORKS - A technique in which an outgoing signal is encoded to have multiple signal levels to modulate a light source, in which respective signal levels are indicative of different signal states of more than one bit. The multi-level signal is transmitted on a passive optical network (PON) having passive splitters to split the modulated light to transmit the light having multiple signal levels to a plurality of destinations via the PON. | 10-30-2014 |
20140356002 | FLATTENED OPTICAL FREQUENCY-LOCKED MULTI-CARRIER GENERATION BY ONE DML AND ONE PHASE MODULATOR - The disclosure relates to a method for optical frequency-locked multi-carrier generation based on one directly-modulated laser (DML) and one phase modulator (PM) in cascade driven by sinusoidal waveform (at the same or different frequency). When the DML and PM is driven by the same frequency RF signal at 12.5 GHz, adopting this method, 16 optical subcarriers with 12.5-GHz frequency spacing are generated with power difference less than 3 dB. When the DML and PM is driven by the different frequency with DML at 12.5 Ghz and PM at 25 GHz, over 24 optical subcarriers are generated with 12.5-GHz frequency spacing and amplitude fluctuation less than 3 dB. The number of the generated optical subcarriers can be further increased when the driving power for the DML is increased. | 12-04-2014 |
20150117869 | OPTICAL MULTILEVEL TRANSMITTER AND OPTICAL TRANSPONDER - An optical multilevel transmitter includes a semiconductor quadrature optical modulator configured to separately modulate and output in-phase and quadrature electric field components and a semiconductor nonlinear characteristic compensation circuit configured to generate, from in-phase and quadrature drive signals to be inputted to the semiconductor quadrature optical modulator, two signals for correcting each other and to add the two correcting signals to the corresponding drive signals. | 04-30-2015 |
20150125160 | METHOD AND APPARATUS FOR DIRECTLY DETECTED OPTICAL TRANSMISSION SYSTEMS BASED ON CARRIERLESS AMPLITUDE-PHASE MODILATION - Methods and apparatus for directly detected optical system based on gapped CAP modulation and DSP Methods for generation and reconstruction of gapped CAP signal are disclosed. An apparatus for direct detection transmission for CAP modulated signal with two unbalanced optical sidebands separated by gaps is disclosed, in which a gapped CAP signal is generated, converted, and passed to an optical filter for unbalanced sidebands generation and wavelength locking before being transmitted over an optical link. Direct detection is performed on the optical signal and passed to gapped matching filters. Channel equalization is performed and the signal information is decoded to binary data. | 05-07-2015 |
20160127046 | System and Method for Multi-Dimensional Modulation Using Multiple Constellations - A system and method including multi-dimensional coded modulation wherein symbols within successive blocks of symbols are mapped using at least two different constellations to differentiate the symbols from each other. At least one data bit is encoded by an order of the symbols within each block of symbols. The receiver decodes the data by decoding at least one bit from the order of the symbols mapped with the first and second constellations. | 05-05-2016 |
20160127166 | SYSTEM AND METHOD FOR MULTI-DIMENSIONAL MODULATION USING MULTIPLE CONSTELLATIONS - A system and method including multi-dimensional coded modulation wherein symbols within successive blocks of symbols are mapped using at least two different constellations to differentiate the symbols from each other. At least one data bit is encoded by an order of the symbols within each block of symbols. The receiver decodes the data by decoding at least one bit from the order of the symbols mapped with the first and second constellations. | 05-05-2016 |
20170237505 | OPTICAL DEVICE, A TRANSMITTER FOR A QUANTUM COMMUNICATION SYSTEM AND A QUANTUM COMMUNICATION SYSTEM | 08-17-2017 |
20190149242 | DISTRIBUTION MATCHING FOR PROBABILISTIC CONSTELLATION SHAPING WITH AN ARBITRARY INPUT/OUTPUT ALPHABET | 05-16-2019 |