Sumitomo Electric Industries, Limited

Chie Fukuda

Masashi Onishi

Hiroo Kanamori

Tetsuya Hattori

Morihiro Seki

Takashi Kato

Keiji Tanaka

Toshimitsu Kaneko

Motoki Kakui

Naoya Kono

Taizo Tatsumi

Hiroshi Kohda

Naoki Itabashi

Phillip J Edwards

Yasuyuki Yamauchi

Kazuhiro Yamaji

Hiroyuki Ichikawa

Koji Amemiya

Lance Thompson

A wavelength monitor monolithically integrated with a tunable LD is disclosed. The wavelength monitor includes at least two filters, each filter having a different periodic transmission spectrum. A transmittance of the first filter, and another transmittance of the second filter at a grid wavelength attributed to a WDM system forms a combination which is specific to the grid wavelength but different from other combinations at other grid wavelengths.

Wavelength monitor, wavelength lockable laser diode and method for locking emission wavelength of laser diode

A semiconductor optical modulator includes optical input and output portions; a plurality of Mach-Zehnder modulators, each including first and second waveguide arms having first and second modulation electrodes, respectively; an optical demultiplexer coupled between the optical input portion and the Mach-Zehnder modulators through an optical waveguide; an optical multiplexer coupled between the optical output portion and the Mach-Zehnder modulators; a plurality of electrical inputs; and a plurality of differential transmission lines electrically connecting the electrical inputs to the Mach-Zehnder modulators. The first modulation electrode and the second modulation electrode of at least one of the Mach-Zehnder modulators, one of the electrical inputs, and one of the differential transmission lines that connects such one electrical input to such one Mach-Zehnder modulator form an electrical circuit having a differential impedance in a range of 80&#x3a9; to 95&#x3a9;.

Optical modulator module and semiconductor optical modulator

A semiconductor laser includes a gain region; a distributed Bragg reflector (DBR) region including a diffraction grating; an end facet facing the DBR region with the gain region arranged therebetween; a first ring resonator including a first ring-like waveguide and a first optical coupler; a second ring resonator including a second ring-like waveguide and a second optical coupler; and an optical waveguide that is optically coupled to the end facet and extending in a predetermined optical-axis direction. The first and second ring resonators are optically coupled to the optical waveguide through the first and second optical couplers, respectively. Also, the DBR region, the gain region, and the end facet constitute a laser cavity. Further, the first ring resonator has a free spectral range different from a free spectral range of the second ring resonator.

Semiconductor laser

A method for making a polarization rotator includes the steps of forming a structure including a semiconductor substrate and a mesa part, forming a first semiconductor layer on a main surface of the semiconductor substrate and around the mesa part, forming a second semiconductor layer on the first semiconductor layer, forming a semiconductor laminate by forming a third semiconductor layer on the second semiconductor layer, forming a mask layer on the third semiconductor layer, forming a mesa including a first semiconductor core by etching the semiconductor laminate, and forming a first semiconductor cladding by forming a fourth semiconductor layer around the mesa. The first semiconductor core and the first semiconductor cladding form a polarization rotating unit. An inclined surface of a mesa-part-adjacent portion extends in a second direction forming an acute angle with the main surface. An inclined portion of the second semiconductor layer extends in the second direction.

Method for making polarization rotator and the polarization rotator made thereby

A semiconductor laser according to the present invention includes a first reflective region and a second reflective region disposed opposite to the first reflective region in a predetermined direction of an optical axis. The first reflective region has a plurality of gain waveguides each including an active layer and a plurality of refractive-index controlling waveguides each having a first diffraction grating formed therein. The gain waveguides and the refractive-index controlling waveguides are alternately arranged at a predetermined pitch in the direction of the optical axis. The second reflective region has a second diffraction grating.

Semiconductor laser and method for manufacturing the same

A semiconductor laser includes a light emission end facet; a first optical waveguide extending in a predetermined optical-axis direction, the first optical waveguide being optically coupled to the light emission end facet; a ring resonator having a plurality of periodic transmittance peak wavelengths, the ring resonator being optically coupled to the first optical waveguide; a plurality of gain waveguides that generate light by injection of current; an optical coupler portion that optically couples the first optical waveguide to each of the plurality of gain waveguides; and a plurality of second optical waveguides including diffraction gratings, the plurality of second optical waveguides being respectively optically coupled to the plurality of gain waveguides. Also, each of the diffraction gratings in the plurality of second optical waveguides has a different reflection band.

A semiconductor optical modulation device includes a substrate; a first semiconductor cladding layer of a first conductivity type disposed on the substrate; an optical waveguide layer disposed on the first semiconductor cladding layer, the optical waveguide layer including a first semiconductor optical confinement layer, a second semiconductor optical confinement layer, and an insulating layer disposed between the first semiconductor optical confinement layer and the second semiconductor optical confinement layer, the insulating layer being made of aluminum oxide; a second semiconductor cladding layer of a second conductivity type disposed on the optical waveguide layer; a first electrode electrically connected to the first semiconductor cladding layer; and a second electrode electrically connected to the second semiconductor cladding layer.

Semiconductor optical modulation device, Mach-Zehnder interferometer type semiconductor optical modulator, and method for producing semiconductor optical modulation device

A semiconductor laser includes a semiconductor laser region and a wavelength-monitoring region. The semiconductor laser region includes a first optical waveguide that includes a gain waveguide, the first optical waveguide having one end and another end opposite the one end. The wavelength-monitoring region includes a second optical waveguide that is optically coupled to the first optical waveguide with the one end therebetween, and a photodiode structure that is optically coupled to the second optical waveguide. In the wavelength-monitoring region, the second optical waveguide is branched into three or more optical waveguides, and at least two optical waveguides among the three or more optical waveguides form first ring resonators having optical path lengths different from each other.

A semiconductor laser device includes a laser diode provided on a semiconductor substrate, the laser diode including a first optical waveguide having a gain waveguide, a plurality of photodiodes, a first wavelength-selective filter having periodic transmission peaks, and a second wavelength-selective filter having periodic transmission peaks, the period of the transmission peaks of the second wavelength-selective filter being different from the period of the transmission peaks of the first wavelength-selective filter. Furthermore, two photodiodes among the plurality of photodiodes are optically coupled to the first optical waveguide through the first and second wavelength-selective filters, respectively.

Semiconductor laser device

A wavelength tunable laser includes a first facet including a high reflection coating film; a gain region disposed adjacent to the first facet, the gain region including two or more light emitting devices that are arranged parallel to one another; an optical wavelength multiplexer optically connected to the light emitting devices; and an optical reflector disposed adjacent to a second facet opposite the first facet, the optical reflector having a reflection spectrum with periodic reflection peaks. The optical wavelength multiplexer is disposed between the gain region and the optical reflector, and the optical reflector and the first facet including the high reflection coating film form a laser cavity.

Wavelength tunable laser

A wavelength tunable laser according to the present invention includes a first facet and a second facet opposite the first facet, a reflective region provided adjacent to the second facet, and a gain region provided between the first facet and the reflective region. The reflective region has a plurality of reflection peak wavelengths that periodically vary at a predetermined wavelength interval. The first facet and the reflective region constitute a laser cavity. Furthermore, the gain region includes an active layer where light is generated, a diffraction grating layer having a diffraction grating whose grating pitch varies in a light propagation direction, a refractive-index control layer provided between the active layer and the diffraction grating layer, a first electrode for injecting current into the active layer, and a plurality of second electrodes arranged in the light propagation direction to inject current into the refractive-index control layer.

The present invention is to provide a method for producing a semiconductor laser diode (LD) with an enhanced ESD resistance. The method includes a step for forming an aluminum film on a facet of the LD and a step for forming an aluminum oxide film on the aluminum film. The underlying aluminum film is oxidized during the formation of the aluminum oxide film to form a double aluminum oxide layer. The ratio of the oxide composition of the underlying aluminum oxide film is smaller than that of the upper aluminum oxide film.

Method for forming a coating film on a facet of a semiconductor laser diode

A method of manufacturing an optical waveguide device that is capable of reducing the imbalance in the refractive index profile of a core, and an optical waveguide device that has the reduced imbalance in the refractive index profile are provided. The method of manufacturing an optical waveguide device has the steps of forming a groove in a first cladding layer having a first dopant that lowers the refractive index of the first cladding layer below the refractive index of pure silica glass, forming a core in the groove, and forming a second cladding layer having a second dopant that lowers the refractive index of the second cladding layer below the refractive index of pure silica glass, over the first cladding layer and the core.

Optical waveguide device and method of manufacturing same

An optically amplifying waveguide that can have a gain having a small wave-length dependency in a wavelength range shorter than the C-band, and the like. The optical amplifier moduleoptically amplifies a signal lightwave that has a wavelength lying in a wavelength range of 1,490 to 1,530 nm and that has entered an input connectorto output the optically amplified signal lightwave from an output connectorAn optical isolatora WDM coupleran Er-doped optical fiber (EDF)a WDM couplerand an optical isolatorare provided in this order on a signal lightwave-transmitting path from the input connectorto the output connectorA pump sourceconnected to the WDM couplerand a pump sourceconnected to the WDM couplerare also provided. In the EDFat least one of the stimulated-emission cross section and the absorption cross section assumes a maximum value at the shorter-wavelength side of a peak at a wavelength range of 1.53 &#x3bc;m.

Optically amplifying waveguide, optical amplifier module, and optical communication system

To provide an optical device whereby the optical characteristics of a lightwave circuit element can be varied with low power consumption. There is provided an optical device comprising a lightwave circuit element having one or plurality of optical waveguides, and also having a refractive index adjusting portion composed of resin located in the one or plurality of optical waveguides and/or in a portion of the area in the one or plurality of optical waveguides. The lightwave circuit element comprises an adjustment-light waveguide for guiding adjustment light that varies the refractive index of the resin, and directing the adjustment light to the adjusting portion.

Growing community of inventors

Yokohama, Japan

Chie Fukuda