Fujitsu Corporation

Fujitsu Optical Components Limited

Koji Terada

Haruhiko Tabuchi

Hiroyuki Nobuhara

Jun Matsui

Kohei Shibata

Terukazu Naruse

Kazuhiro Tanaka

Takashi Shimizu

Kazuyuki Mori

Satoshi Ide

Hidehiko Nakata

Tsuyoshi Yamamoto

Goji Nakagawa

Yoshihiro Yoneda

Tamotsu Akashi

Yuji Ishii

Kazunori Miura

Akira Fukushima

Kenichi Kawazoe

Taizo Nosaka

Kiyomi Narita

An optical receiver receives coherent light. The optical receiver includes an amplitude adjuster, a signal processor, and a controller. The amplitude adjuster adjusts amplitude of an input signal to output an analog signal. The signal processor receives a digital signal generated from the analog signal output from the amplitude adjuster, extracts clock components from the digital signal, and after establishing synchronization between the clock components and data components, extracts the data components from the digital signal to process the data components. The controller sets amplitude of the analog signal to first amplitude before establishment of synchronization by the digital signal, and changes the set amplitude to second amplitude that is smaller than the first amplitude after the establishment of synchronization.

Optical receiver and light receiving method

A light reception device includes: an interferometer that outputs a signal obtained by making an optical phase modulated signal interfere with a reference signal after shifting an optical phase of the optical phase modulated signal by a given amount; a light reception element that receives an output signal from the interferometer and converts the output signal into a light reception current; and a phase controller that controls a control amount in controlling the given amount so that a value of a function, which is calculated based on an amount relating to the light reception current and a change amount of an amount relating to the light reception current against the control amount, becomes an extreme value or 0.

Light reception device and method for controlling the same

A demodulator includes: a splitter that branches a differential phase shift keying optical signal into a first branched optical signal passing through a first optical path and a second branched optical signal passing through a second optical path; a multiplexer that multiplexes the first branched optical signal having passed through the first optical path and the second branched optical signal having passed through the second optical path and makes interference between the first branched optical signal and the second branched optical signal; and a double refraction medium that reduces difference between phase differences between each polarized wave between the first branched optical signal and the second branched optical signal multiplexed by the multiplexer.

Demodulator and receiving device

An optical receiving circuit receives and demodulates an optical signal subjected to phase modulation and wavelength division multiplexing. The optical receiving circuit includes an interfering unit that causes a reference signal to interfere with the optical signal to output resulting signals as positive-phase signals and negative-phase signals; and a wavelength separator having input ports receiving the positive-phase signals and the negative-phase signals, the positive-phase and negative-phase signals being adjacent to each other. The wavelength separator separates according to wavelength, the positive-phase signals and the negative-phase signals, and from output ports, outputs for each wavelength, a separated positive-phase signal and negative-phase signal in a state of being adjacent to each other. The optical receiving circuit further includes balanced receivers respectively provided for each wavelength, where a given balanced receiver for a given wavelength performs balanced reception and demodulation of the separated positive-phase signal and negative phase signal of the given wavelength.

Optical receiving circuit

A demodulator and method are provided. The demodulator for demodulating an optical signal, includes a splitter that splits a differential phase modulation signal into a first split light component and a second split light component, couples the first split light component to a first optical path and the second split light component to a second optical path, a first medium disposed on the first optical path, a second medium disposed on the second optical path and having a refractive index different from that of the first medium, and a combiner that combines the first split light component that has passed through the first medium and the second split light component that has passed through the second medium, wherein one of the first split light component and the second split light component is delayed in relation to the other.

Demodulator

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

The present invention is a wavelength superimposing device that can restrain a system scale and further reduce an optical transmission loss, while broadcasting a video signal light in a WDM network system, a manufacturing method therefor, and the WDM network system, and comprises a filter device that reflects some light of an input wavelength-multiplexed light in a direction different from an optical path direction of the input wavelength-multiplexed light and transmits a light of remaining wavelengths, a first optical system in which a reflected light reflected by the filter device is re-incident on a plurality of incident positions on a reflecting surface of the filter device, and a second optical system in which a transmitted light from the filter device is spectrally separated for each wavelength and each separated light is incident on the plurality of incident positions from a transmission surface of the filter device.

Wavelength superimposing device, manufacturing method therefor, and WDM network system

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.

Optical module

The present invention provides substrate 10, capable of transmitting lights in thickness direction for enhancing usefulness of the substrate. Its object is to provide a substrate adapted for interconnecting optical elements, allowing reduction of number of components leading to miniaturization and low cost, and high-efficient and stable optical coupling leading to low electric power dissipation. To accomplish the object the substrate comprises substrate body, wherein it is comprised of electric wiring layer disposed on first substrate body surface in such a manner as to be capable of electrically connecting first optical element mounted on the side of first substrate body surface; and optical transmission path, propagating lights being transmitted and received between first optical element electrically connected at electric wiring layer and second optical element disposed on the side of second substrate body surface different from first substrate body surface in substrate body.

Substrate, substrate adapted for interconnecting optical elements and optical module

An optical device enabling reducing device scale is constituted by M circulators (), (M being a natural number), a waveguide-type diffraction grating () including M first input/output waveguides () formed at its one end and M&#xd7;N second input/output waveguides (-to-N and-to-N) formed at the other end, (N being a natural number), and paths from the M circulators being connected to the M first input/output waveguides; and N reflection-type optical switches (-to-N) each for reflecting the optical paths for M adjacent waveguides out of the M&#xd7;N second input/output waveguides(-to-N and-to-N) and for switching over the returning-destination waveguide respectively, wherein the M circulators, the waveguide-type diffraction grating and N reflection-type optical switches are arranged in cascade. Consequently, the optical device can function preferably also as a wavelength selective optical switch available in a WDM transmission system.

Wavelength selective and level adjusting optical device

An optical device used, for example, in an add/drop multiplexer, a dynamic gain equalizer or a optical power monitor. The optical device includes (a) a substrate; (b) a first slab waveguide formed on the substrate; (c) channel waveguides of differing lengths formed on the substrate, light output from the first slab waveguide being input to the channel waveguides; and (d) a second slab waveguide formed on the substrate, light output from the channel waveguides being input to the second slab waveguide. An end face of the second slab waveguide shares a face with an end face of the substrate. The optical device has low loss characteristics.

Optical device with slab waveguide and channel waveguides on substrate

An optical wavelength switch having a planar wave-guide formed on a substrate including a wave-guide-type diffraction grating having an input/output wave-guide with an under-clad layer on a sacrificial layer formed on the substrate, a core layer formed on the under-clad layer and an over-clad layer formed on the core layer. The switch including a first slab wave-guide connected with the input/output wave-guide, an array wave-guide with one side connected to the first slab wave guide, a second slab wave-guide connected to the other side of the array wave-guide, and a movable girder secured to the substrate. The movable girder has the same under-clad layer, core layer and over-clad layer as the wave-guide-type diffraction grating. The switch has a minor at the tip of the movable girder, the mirror facing an end face of the second slab wave-guide, and the displaceable along a direction perpendicular to the optical axis.

Growing community of inventors

Kawasaki, Japan

Koji Terada