Fujitsu Corporation

Jun Matsui

Tsuyoshi Yamamoto

Koji Terada

Hiroyuki Nobuhara

Takashi Shimizu

Tomoyuki Akiyama

Shinsuke Tanaka

Takeshi Hoshida

Satoshi Ide

Takatoshi Yagisawa

Eiji Yoshida

Hisakatsu Yamaguchi

Hidehiko Nakata

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

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

A method includes transmitting a data signal generated by adjusting a phase of a data signal, receiving a control signal having a frequency lower than that of the data signal and used to control an apparatus of a transmission destination of the data signal, and applying, in a case where a signal level of the control signal is a level, jitter to the data signal by periodically changing a magnitude of an additional phase code to be added to a phase code representative of an adjustment amount for the phase but fixing, in a case where the signal level is a level different from the level, the additional phase code to 0, receiving the data signal and adjusting a phase of the data signal to generate a data signal and restoring the control signal from a phase code representative of an adjustment amount for the phase.

Control signal transmission and reception system and control signal transmission and reception method

An optical receiving device includes: a lens portion configured to refract incident light with a first wavelength and refract incident light with a second wavelength; a first beam splitter configured to let refracted light with the first wavelength transmit and reflect refracted light with the second wavelength; a second beam splitter configured to reflect transmitted light with the first wavelength; and a light receiver configured to receive reflected light with the first wavelength and reflected light with the second wavelength, wherein the first beam splitter and the second beam splitter are disposed so as to be separated by a difference in optical path length between the light with the first wavelength and the light with the second wavelength.

Optical receiving device including first lens and second lens and optical receiving system including first lens and second lens

An optical fiber includes a core, a cladding, and a thermally conductive member. The cladding is formed in a surrounding of the core. The thermally conductive member is formed in a surrounding of the cladding and includes a thermal conductivity higher than thermal conductivities of the core and the cladding.

Optical fiber and optical fiber manufacturing method

A decision circuit includes: a first decision block to distinguish a first bit of bits using an amplitude of an analog signal as a discrimination point, the analog signal being an amplitude shift keyed signal; a superposition block to acquire an absolute value of a difference of the analog signal in respect to an amplitude center value of the analog signal by superposing divided analog signals; an inversion block to control inverting of the signal based on a first distinction result of the first decision block; a second decision block to distinguish a second bit of the bits based on an amplitude of an output signal from the inversion block and the discrimination point; and an output buffer to output the first distinction result and a second distinction result of the second decision block in synchronization with a clock.

Decision circuit, receiver device, and processor

An apparatus for correcting a signal, includes a correction value calculator that determines a transmission distance of a transmission path through which a timing signal is propagated, the timing signal having a periodically changing frequency, and determines a deviation between a frequency of the timing signal and a frequency of received data, as a correction value, from the transmission distance; and a corrector that corrects the frequency of the timing signal by the correction value for synchronizing transmitted data with the timing signal.

Apparatus for correcting signal, transmission apparatus, method of correcting signal, and transmission system

An optical transmission system including a transmitting unit to transmit an optical main signal, a receiving unit to receive the optical main signal, and a transmission line through which the optical main signal is transmitted, the optical transmission system includes: an optical transmitter unit configured to be activated or inactivated based on a control signal so as to transmit the control signal, the optical transmitter being included in the transmitting; and an optical receiver configured to receive light with the activate state or the inactivate state of the optical transmitter the optical receiver being included in the receiving unit, wherein the receiving unit regenerates the control signal, based on a power of the received light.

Optical transmission system, control signal transmission method, and optical module

An optical transmission apparatus includes a transmitter that transmits to a counterpart receiver via a transmission path and transmits as optical signals for a plurality of channels, input signals for a plurality of channels; and a controller that when a transmission failure between the transmitter and the receiver is detected, distributes to properly operating channels, data for a channel subject to the transmission failure, increases a transmission rate for the properly operating channels to a given transmission rate, and continues data transmission for all channels including the channel subject to the transmission failure.

Optical transmission apparatus and optical transmission method

A device includes: a providing unit that provides a driving electric current to a semiconductor laser, the electric current being superimposed a first alternating current signal having a first frequency at a low side of an operational range of the semiconductor laser and a second alternating current signal having a second frequency at a high side of the operational range; a first filter that extracts a first component corresponding to the first frequency from a voltage to be applied to the semiconductor laser; a second filter that extracts a second component corresponding to the second frequency from the voltage to be applied to the semiconductor laser; and a judge circuit that judges a state of the semiconductor laser based on a first differential resistance obtained from the result of the extracting by the first filter and a second differential resistance obtained from the result of the extracting by the second filter.

Device for judging state of semiconductor laser and method for judging state of semiconductor laser

An optical connector includes a fiber-support block configured to couple cores of a plurality of optical fibers, and a lens-support block including a contact surface provided with a plurality of openings, the contact surface contacted to a contact surface of the fiber-support block, the cores of the optical fibers projecting from the contact surface of the fiber-support block insertable into the respective openings, the lens-support block having pairs of collimate lenses and convex lenses in the respective openings, each of the collimate lenses and a corresponding one of the convex lenses being spaced apart from each other in an optical-axis direction, the collimate lenses being movable in the optical-axis direction and being pressed by elastically deformable members, respectively, in the optical-axis direction and toward the contact surface of the fiber-support block.

Optical connector and method of connecting fiber array

A first wiring board, which is a flexible printed-circuit board, is bonded to a second wiring board. A plurality of protruding member are formed on the surface of the second wiring board. An adhesive is deposited on the surface of the second wiring board such that there is a thinner layer of the adhesive on the protruding member than in other areas. Subsequently, the first wiring board is placed on the second wiring board so that a portion of the first wiring board to be used for the wire-bonding is positioned above at least one of the protruding members. The first wiring board gets bonded to the second wiring board due to the adhesive.

Flexible printed-circuit boards bonding method and printed circuit board

Electrical connection is established by bringing solder bumps formed as electrical connecting terminals of an electronic part and spiral contactors formed as electrical contactors of a circuit substrate into contact with each other. The solder bumps are formed such that heights thereof relative to a surface on which the solder bumps are formed are different from each other.

Electronic part and circuit substrate

An optical module according to the present invention comprises an electric wiring substrate, a first optical element mounted on the electric wiring substrate so that a heat generation section of the first optical element is positioned relatively close to a substrate surface of the electric wiring substrate and a heat sink mounted on the same plane as the mounting plane of the first optical element on the electric wiring substrate, the heat sink being mounted on the electric wiring substrate so that an area of electric wiring on the electric wiring substrate overlaps the heat sink. This improves the efficiency of heat radiation of the optical module.

Optical module and manufacturing method thereof

An optical module includes a photoelectric element that performs a conversion between an optical signal and an electric signal; a body having a first surface and a second surface, the first surface and the second surface being continued and adjacent to each other; and an electric circuit board that is mounted on the body, the electric circuit board having a bending portion that is bent along the first surface and the second surface. The photoelectric element is mounted on one portion arranged on the first surface bordering on the bending portion. An electric wiring board on which a wiring unit for an external connection is formed is mounted on other portion arranged on the second surface.

Growing community of inventors

Kawasaki, Japan

Jun Matsui