Fujitsu Corporation

Kokusai Denshin Denwa Kabushiki Kaisha

Fujitsu Hitachi Plasma Display Limited

Photonics Electronics Technology Research Association

Kokusai Denshin Denwa Co., Ltd.

Hitachi, Ltd.

Hitachi Plasma Patent Licensing Co., Ltd.

Shinsuke Tanaka

Ken Morito

Tomoyuki Akiyama

Nobutake Imamura

Chuichi Ota

Takeshi Hoshida

Yohei Sobu

Hitoshi Hirakawa

Yuichi Matsushima

Kazumasa Takabayashi

Tatsuya Usuki

Jun Matsui

Ayahito Kojima

Shigeaki Sekiguchi

Susumu Yamazaki

Masayoshi Horita

Shunji Oota

Tsuyoshi Yamamoto

Yoshikazu Kanazawa

Katsuyuki Utaka

Makoto Onozawa

Naoki Matsui

Toshihiko Mori

Fumitaka Asami

Masaya Tajima

Shigeharu Asao

Hideaki Ohki

Katsuhiro Ishida

Eiji Ito

Yasuhiro Nakasha

Kenichi Kawaguchi

Takashi Shiizaki

Haruhiko Kuwatsuka

Yasuyuki Nagao

Ayahito Uetake

Satoru Nishimura

Fujio Tanaka

Takashi Fujisaki

Yoshimasa Awata

Nobuyoshi Kondo

Lei Zhu

Kiyoshi Takata

Junichi Okayasu

Kunio Umehara

An optical transceiver includes: an optical transceiver circuit; a light source device to multiplex light rays emitted from light source elements having different wavelengths, and output multiplexed light; a demultiplexer to demultiplex the light output from the light source device into wavelengths to supply the wavelengths to the optical transceiver circuit; monitors to monitor the wavelengths at output ports of the demultiplexer, respectively; and a wavelength controller to control the wavelengths of the light source elements, based on monitoring results of the monitors, wherein the demultiplexer includes unit circuits in each of which three asymmetric Mach-Zehnder interferometers having a predetermined arm length difference are cascaded in a tree shape, and each of the monitors is arranged at an output waveguide of an asymmetric Mach-Zehnder interferometer at an end of the cascaded tree, to be connected to the wavelength controller via a signal line.

Optical transceiver, optical transceiver device using the same, and method of controlling light source wavelengths

Optical transmitter includes: signal processing circuit, optical modulator, optical filter, and delay circuit. The signal processing circuit generates N drive signals for generating a modulated optical signal. Symbol rate of the modulated optical signal is fs and each symbol of the modulated optical signal transmits N bits. The optical modulator includes Mach-Zehnder interferometer and N phase-shift segments each of which shifts a phase of light propagating through an optical path of the Mach-Zehnder interferometer according to the N drive signals. The optical filter removes, from output light of the optical modulator, a frequency component in a range of ±fs/2 with respect to a center frequency of the modulated optical signal, and extracts at least a part of other frequency components. The delay circuit controls timings of the N drive signals so as to reduce optical power of the frequency component extracted by the optical filter.

Optical transmitter that transmits multi-level optical signal

An optical communication element includes a plurality of slabs, an input port group, an output port group, a first waveguide group, and a second waveguide group. The plurality of slabs includes third waveguide. Each of the plurality of slabs include a predetermined number of first ports being arranged at an inlet the third waveguide at equal intervals in a lateral direction perpendicular to a light traveling direction, and input the optical signals, and a predetermined number of second ports being arranged at an outlet of the third waveguide at the equal intervals in the lateral direction so as to face the first ports, and output the optical signals. Each of the third waveguides are configured with a dimension that allows light intensity to be distributed at all traveling positions located in the lateral direction.

Optical communication element and optical neural network

An optical analog-to-digital (AD) converter includes, wherein the optical AD converter converts an analog signal of information included in inputted signal light into a digital signal, and is formed of N stages corresponding to a number N of bits of the digital signal, optical waveguides configured to respectively guide the signal light, base light obtained by branching local light, and reference light obtained by branching the local light, a light receiver configured to detect and compare light levels of the signal light and the reference light, and output a binary comparison result, and an optical modulator configured to variably control a light level of the base light, based on the binary comparison result, in each stage of the N stages, wherein an output variably controlled of the optical modulator is multiplexed with the reference light of a next stage.

Optical AD converter and optical receiver

An optical demultiplexing device includes a light source, a demultiplexer, a plurality of converters, a detector, a switch, and a controller, wherein the demultiplexer includes a plurality of asymmetric Mach-Zehnder interferometers (AMZ) each of which lengths of a pair of arms are different from each other, the plurality of AMZs are coupled to each other so that a plurality of wavelength lights input from the light source is demultiplexed and respectively output to the converters different from each other, and the controller controls the light source so that the plurality of wavelength lights is sequentially input to the demultiplexer one by one, and controls the switch so that an electrical signal detected by the detector is output to an output destination according to a wavelength light of a conversion source of the electrical signal.

Optical demultiplexing device and transmission device

An optical transmitter transmits a modulated optical signal in which each symbol carries M bits. M is an integer larger than one. The optical transmitter includes: a signal generation circuit configured to generate M&#xd7;N binary electric signals based on transmission data, bit rates of the M&#xd7;N binary electric signals being equal to each other, N being an integer larger than one, when the optical transmitter multiplexes N optical signals in time-division multiplexing; a Mach-Zehnder interferometer; and M&#xd7;N phase-shift elements provided along an optical path of the Mach-Zehnder interferometer and respectively configured to shift phases of light propagated in the optical path corresponding to the M&#xd7;N binary electric signals. The M&#xd7;N phase-shift segments are comprised of N electrode groups. Each of the N electrode groups includes M or more electrodes to which corresponding M binary electric signals among the M&#xd7;N binary electric signals are given.

Optical transmitter for transmitting multilevel optical signals

A wavelength tunable light source includes: a common wavelength filter that has periodic transmission peak wavelengths or reflection peak wavelengths and is commonly used for a plurality of channels; a wavelength tunable filter that is coupled to the common wavelength filter and has a one-input and multiple-output configuration which has a plurality of output ports, and that has a plurality of transmission peak wavelengths corresponding to the plurality of channels at the plurality of output ports; and a plurality of gain media optically coupled to the plurality of output ports of the wavelength tunable filter, wherein a plurality of laser cavities that perform laser oscillation at a plurality of different wavelengths are formed between the common wavelength filter and the plurality of gain media.

Wavelength tunable light source, optical transmission apparatus using the same, and method of controlling wavelength tunable light source

An optical modulator, that includes a Mach-Zehnder interferometer and three or more segments, generates an optical signal based on three or more electric signals transmitted in parallel. The three or more segments are provided in series along an optical path of the Mach-Zehnder interferometer and respectively shift a phase of light propagating through the optical path based on the three or more electric signals. A length of at least one of the three or more segments is different from lengths of the other segments. Optical path lengths from input ends of respective segments to input ends of corresponding next segments are the sae.

Optical modulator and optical modulation method

A transmission device including a multi-division optical modulator having a plurality of modulation segments, the transmission device includes a driver circuit configured to output binary data for each bit based on an input electrical signal, and an optical modulator configured to have a multilevel modulation segment driven by a first drive signal including two or more bit signal from the driver circuit, and plural binary modulation segments driven by second drive signal including only one bit signal from the driver circuit, wherein the multilevel modulation segment incudes a first phase shifter disposed on each arm of the optical modulator, the binary modulation segment includes a plurality of second phase shifters arranged along each arm of the optical modulator, and lengths of the second phase shifters are all the same and are shorter than a length of the first phase shifter.

Transmission device, optical transceiver module, and optical modulation method

An optical transmitter-receiver includes an optical integrated device in which at least an optical modulator and an optical detector are integrated as optical devices over the same substrate and an insulating layer is provided between the optical modulator and the substrate and between the optical detector and the substrate, and an electronic circuit chip that is connected to the optical integrated device and includes an electronic circuit including a ground wiring line. The optical integrated device includes a shield electrode between the optical modulator and the optical detector, and the shield electrode is provided sandwiching the insulating layer with the substrate to configure a capacitance and is connected to the ground wiring line of the electronic circuit chip. By the optical transmitter-receiver, crosstalk through the capacitance between the optical modulator and the substrate, the substrate, and the capacitance between the optical detector and the substrate can be suppressed to suppress deterioration of the reception characteristic.

Optical transmitter-receiver

An optical transmitter includes: a driving circuit that includes drivers each corresponding to a configuration bit of an input electrical data sequence; a MZ optical modulator that includes a first phase shifter provided in an arm and a second phase shifter provided in an arm; first capacitance elements that are electrically connected between the driving unit and the first phase shifter, each include an electric capacity weighted in response to a bit number of the configuration bit, and generate a first multilevel signal to be supplied to the first phase shifter; and second capacitance elements that are electrically connected between the driving circuit and the second phase shifter, each include an electric capacity weighted in response to a bit number of the configuration bit, and generate a second multilevel signal to be supplied to the second phase shifter.

Optical transmitter, optical modulator module, and optical transmission system

The invention relates to a wavelength division multiplexing optical receiver that is provided with a polarization splitting grating coupler and a driving method for the same, where the power consumption is reduced, and at the same time, a degradation in the receiver sensitivity is suppressed. Two monitor photodetectors configured to monitor the light intensity of a first polarization component and a second polarization component separated by a polarization splitting optical coupler are provided, and a control circuit is provided in order to allow a semiconductor optical amplifier that amplifies the first polarization component and another semiconductor optical amplifier that amplifies the second polarization component in accordance with the signal intensity ratio of the two monitor photodetectors to amplify light with different light gains.

Wavelength division multiplexing optical receiver and driving method for same

An optical device includes a silicon waveguide core having a tapered portion having a sectional size that decreases toward a terminal end portion thereof, a dielectric waveguide core contiguous to the silicon waveguide core while covering at least the tapered portion, the dielectric waveguide core having a refractive index lower than that of the silicon waveguide core and configuring a single-mode waveguide, and a diffraction grating provided at the single-mode waveguide and configuring a distributed Bragg reflection mirror.

Optical device, optical transmission device, optical reception device, hybrid laser and optical transmission apparatus

A receiving-side integrated optical circuit of an optical transceiver has an optical wavelength demultiplexer to separate signal light components of the different wavelengths contained in a wavelength division multiplexed signal received from each of N links of a transmission path, a set of N optical amplifiers inserted between the transmission path and the optical wavelength demultiplexer, each optical amplifier being configured to collectively amplify the signal light components of the different wavelengths contained in the received wavelength division multiplexed signal, and a set of photo detectors arranged after the optical wavelength demultiplexer and to detect the signal light components of the different wavelengths.

Optical transceiver and optical output level control method

A manufacturing method for an optical semiconductor device, including disposing a semiconductor element that has a polarization dependent gain or polarization dependent loss between optical waveguide modes differing in the direction of polarization, positioning a lens at one end face side of the semiconductor element based on an optical coupling loss between the lens and the semiconductor element, and repositioning the lens based on the polarization dependent gain or the polarization dependent loss of the semiconductor element.

Optical semiconductor device and manufacturing method therefor

Growing community of inventors

Kawasaki, Japan

Shinsuke Tanaka