Fujitsu Corporation

Fujitsu Optical Components Limited

National Institute of Advanced Industrial Science and Technology

Photonics Electronics Technology Research Association

Fujitsu Limied

Suguru Akiyama

Tsuyoshi Yamamoto

Kazumasa Takabayashi

Haruhisa Soda

Takeshi Baba

Kohei Shibata

Tatsuya Usuki

Kazuhiro Ikeda

Shuntaro Makino

Shigeaki Sekiguchi

Hirotomo Izumi

Takeshi Matsumoto

Hitoshi Kawashima

Ken Tanizawa

Keijiro Suzuki

Yukie Iga

A wavelength filter includes a first filter circuit and a second filter circuit. The first filter circuit that has a passband that is obtained from a vernier effect by connecting, in series, a plurality of ring resonators each having a different transmission wavelength interval and that is within a gain band of an optical amplifier, and that passes, from the gain band, light at a selected wavelength and light that has a wavelength in a recursive mode and that is produced on a short wavelength side or a long wavelength side of the selected wavelength. The second filter circuit is connected to the first filter circuit in series and suppresses the light at the wavelength in the recursive mode from the light passing through the first filter circuit.

Wavelength filter and laser apparatus

An optical amplifier includes an optical amplifier chip that includes a pair of semiconductor optical amplifiers (SOAs), a U-shaped waveguide connecting the pair of SOAS, and two electrodes that respectively correspond to the pair of SOAS and are separated from each other, and a base substrate that includes a common metal wiring connecting the two electrodes, and on which the optical amplifier chip is mounted.

Optical amplifier and inspection method of optical amplifier

An optical amplifier includes a polarization splitter, a polarization rotator, first and second optical couplers, and first and second semiconductor optical amplifying devices. The TE polarized wave of light split by the polarization splitter is input to a first input port of the first optical coupler. The TM polarized wave of the split light is converted into a TE polarized wave by the polarization rotator to be input to a second input port of the first optical coupler. First light and second light output from a first output port and a second output port of the first optical coupler are amplified by the first semiconductor optical amplifying device and the second semiconductor optical amplifying device to be input to a first input port and a second input port of the second optical coupler, respectively. Third light is output from an output port of the second optical coupler.

Optical amplifier and optical switch device

An optical transceiver device includes: an optical circuit that includes an optical modulator to generate a modulated optical signal and an optical reception circuit to convert a received optical signal into an electric signal and implemented in a rectangular optical circuit area; a driver circuit that drives the optical modulator and arranged along a first side of the optical circuit area; an amplifier circuit that converts an output signal of the optical reception circuit into a voltage signal and arranged along a second side of the optical circuit area, the second side being orthogonal to the first side; a first electrical component that is electrically coupled to the driver circuit and arranged in an area adjacent to the driver circuit; and a second electrical component that is electrically coupled to the amplifier circuit and arranged in an area adjacent to the amplifier circuit.

Optical transceiver device and optical transceiver module that includes optical transceiver device

A wavelength locker includes a splitter configured to split a portion of light that is output from a light source into a first monitoring light and a second monitoring light; a first periodic filter configured to receive the first monitoring light; a second periodic filter configured to receive the second monitoring light; a first optical receiver configured to monitor an intensity of light that has passed through the first periodic filter; and a second optical receiver configured to monitor an intensity of light that has passed through the second periodic filter, wherein the first periodic filter and the second periodic filter each has a wavelength characteristic in which an intensity of transmitted light changes periodically with respect to a wavelength, and the wavelength characteristic of the first periodic filter and the wavelength characteristic of the second periodic filter shift in opposite wavelength directions when temperature changes.

Wavelength locker, wavelength tunable laser apparatus, and method for controlling wavelength tunable laser apparatus

A apparatus includes a tunable laser configured to include a tunable filter and a mirror; a first optical splitter provided between the tunable filter and the mirror, the first optical splitter including a first port and a second port on a tunable filter side and a third port and a fourth port on a mirror side, in which the tunable filter is coupled to the first port and the mirror is coupled to the third port, respectively; a first optical waveguide coupled to the second port; a second optical waveguide coupled to the fourth port; and an optical coupler with which the first optical waveguide and the second optical waveguide are combined.

Tunable laser device

An optical modulation device includes: an optical waveguide formed above a substrate; a phase modulator disposed on part of the optical waveguide; a capacitor connected to the phase modulator and including a lower electrode and an upper electrode; a resistor connected in parallel to the capacitor; and an appended part integrated with the upper electrode and electrically connected to the resistor, wherein the appended part is smaller in area than the capacitor (upper electrode).

Optical modulation device

A phase modulation device including a diode-type phase modulator having a pair of side terminals connected to two sides of an optical waveguide core along an optical axis of the optical waveguide core, and a control unit that controls electrical signals to be input to the phase modulator, the side terminal of the phase modulator being divided into a plurality of portions along the optical axis of the optical waveguide core, the phase modulator having electrodesrespectively provided on the divided side terminals and electrically separated from each other, the control unit having switches and constant-current sources connected to the electrodes of the side terminals and controls stepwise the amount of change in phase of propagating light in the optical waveguide core according to the number of the switches turned on.

Phase modulation device and method of controlling the device

The present optical modulator includes an optical waveguide core made of a semiconductor material, an electrode, and a plurality of channels made of a semiconductor material doped in an n type or a p type and electrically connecting the optical waveguide core and the electrode to each other. The plurality of channels are provided in a spaced relationship from each other along a propagation direction of light; the optical waveguide core includes a doped region doped in the n type or the p type and a non-doped region. The doped region and the non-doped region are disposed alternately along the propagation direction of light. Each of the plurality of channels is connected to the doped region.

Optical modulator and optical transmitter

An optical modulation apparatus includes: a substrate; a first optical waveguide and a second optical waveguide formed at an interval on the substrate; an electrode provided along at least one of the first optical waveguide and the second optical waveguide; and a power source coupled to the electrode to apply a voltage to at least one of the first optical waveguide and the second optical waveguide, wherein at least one of the first optical waveguide and the second optical waveguide includes a diffraction grating region where light having a wavelength &#x3bb; is reflected, and a phase shift region where a phase of the light is shifted by an amount in a range of 0 to &#x3bb;/2.

Optical modulation apparatus and optical modulation/integration apparatus

A semiconductor laser includes: a first portion, made from a silicon-containing material, including an optical waveguide, a first diffraction grating including a phase shift, and a second diffraction grating; a second portion including a light-emitting layer made from a material different from that of the first portion; a laser region including the first diffraction grating, and the optical waveguide and the light-emitting layer provided in a position corresponding to the first diffraction grating; and a mirror region including the second diffraction grating, and the optical waveguide and the light-emitting layer provided in a position corresponding to the second diffraction grating.

Semiconductor laser silicon waveguide substrate, and integrated device

In an optical transmitter comprising a directly modulated laser and a wavelength filter provided on a post-stage of the directly modulated laser, the wavelength filter has a modulated light input port for inputting modulated light output from the directly modulated laser, a filter transmitted light output port for outputting light having a wavelength included in a filter transmission band among the modulated light as filter transmitted light, and a filter cutoff light output port provided separately from the modulated light input port and the filter transmitted light output port and outputting light having a wavelength included in a filter cutoff band among the modulated light as filter cutoff light, and the peak of the filter transmission band is set on a shorter-wave side from the peak of the spectrum of modulated light output from the directly modulated laser.

Optical transmitter

A semiconductor device includes an InP substrate, an AlGaInAs-based first layer, an AlGaInAs-based second layer, an InGaAsP-based third layer, and an InGaAsP-based fourth layer. The first and second layers have compositions which are same or substantially same as each other on an interface therebetween. The composition of the layer varies such that a band gap continuously increases from the first layer side toward the third layer side. The compositions of the second and third layers are set such that energy levels of a valence band maximum are substantially equal to each other on an interface between the second and third layers. The composition of the third layer varies such that a band gap continuously increases from the second layer side toward the fourth layer side. The compositions of the third and fourth layers are same or substantially same as each other on an interface between the third and fourth layers.

Semiconductor device

An optical interference unit branching inputted input light into two optical waveguides, combining the respective branched lights propagating through the respective optical waveguides and outputting modulated light is included, and bias voltage supplied to at least one optical waveguide out of the two optical waveguides is controlled in accordance with wavelength of the input light. Further, a phase of the modulated light is controlled by phase adjusting voltage in accordance with the wavelength of the input light.

Growing community of inventors

Kawasaki, Japan

Suguru Akiyama