Abstract: The present invention provides sealing device which is capable of a two-step holding operation with the use of a linear solenoid. The sealing device includes a stopping mechanism for stopping a movement of a movable part that forms the linear solenoid when the linear solenoid is driven at a predetermined midway point between a start point and an end point after the nozzle part has been moved from the waiting position to the stop position, and for releasing the movable part from a stop to allow the movable part to move again and reach the end point after the nozzle part has been returned from the stop position to the waiting position.

Abstract: 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.

Abstract: 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 ? is reflected, and a phase shift region where a phase of the light is shifted by an amount in a range of 0 to ?/2.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 ? is reflected, and a phase shift region where a phase of the light is shifted by an amount in a range of 0 to ?/2.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: There are provided first and second optical waveguides formed on a semiconductor substrate and having upper clad layers and core layers that are separated mutually respectively, first and second phase modulation electrodes formed on the first and second optical waveguides respectively, and first and second slot-line electrodes formed on the semiconductor substrate on both sides of the first and second optical waveguides and connected to the first and second phase modulation electrodes via air-bridge wirings separately respectively.

Abstract: A semiconductor optical modulator, a Mach-Zehnder optical modulator employing the same, and a method of manufacturing a semiconductor optical modulator that are suitable for high-speed baseband communication are provided. An optical waveguide core layer is formed in such a manner that it alternately crosses micro optical modulator elements and gap regions, which are formed by placing electrically insulating material at predetermined intervals on an electrically conductive substrate. The core layer is connected to a signal electrode portion via a conductive semiconductor portion in each micro optical modulator element. A ground electrode is connected to the core layer via the conductive substrate. Further, the signal electrode portions are connected in a series to form a signal electrode by means of in-between metal wirings. Conductive semiconductor material is located between the core layer and the electrodes. In the gap regions, the core layer is sandwiched between insulating semiconductor layers.

Abstract: There are provided first and second optical waveguides formed on a semiconductor substrate and having upper clad layers and core layers that are separated mutually respectively, first and second phase modulation electrodes formed on the first and second optical waveguides respectively, and first and second slot-line electrodes formed on the semiconductor substrate on both sides of the first and second optical waveguides and connected to the first and second phase modulation electrodes via air-bridge wirings separately respectively.

Abstract: A semiconductor optical modulator, a Mach-Zehnder optical modulator employing the same, and a method of manufacturing a semiconductor optical modulator that are suitable for high-speed baseband communication are provided. An optical waveguide core layer is formed in such a manner that it alternately crosses micro optical modulator elements and gap regions, which are formed by placing electrically insulating material at predetermined intervals on an electrically conductive substrate. The core layer is connected to a signal electrode portion via a conductive semiconductor portion in each micro optical modulator element. A ground electrode is connected to the core layer via the conductive substrate. Further, the signal electrode portions are connected in a series to form a signal electrode by means of in-between metal wirings. Conductive semiconductor material is located between the core layer and the electrodes. In the gap regions, the core layer is sandwiched between insulating semiconductor layers.