Abstract: A first multimode interferometer has a first input port to which an optical signal is applied, a first output port, and a second output port. A first optical waveguide is connected to the first output port of the first multimode interferometer. The first optical waveguide has a refractive index changed in response to a trigger signal externally applied. A second optical waveguide is connected to the second output port. A triggering unit supplies, to the first optical waveguide, the trigger signal for changing the refractive index of the first optical waveguide. An optical switch is provided which can increase the processing speed, can reduce the device size, and is free from dependency on the polarization state of an optical signal.

Abstract: An all-optical switch, an all-optical signal waveform reshaping element and an all-optical asymmetric demultiplexer are formed of an optical interferometer having a compact and simple structure. Nonlinear gain media are provided at positions different from each other in two arms of a Mach-Zehnder optical interferometer. Then, an optical cavity is formed by mounting a mirror on an optical input-output port in each of a first and a second multi-mode optical interferometers connected with the two arms. Furthermore, when a saturable absorption medium is placed on the mirror of one of the multi-mode optical interferometers, a mode-locked laser oscillation is induced.

Abstract: The present invention relates to a semiconductor device with quantum dots and a method of manufacturing the same, and a structure of the semiconductor device which can control an emission wavelength of the quantum dots and a method of manufacturing the same are provided. The semiconductor device comprises a compound semiconductor substrate containing at least three elements, and quantum dots which are formed on the compound semiconductor substrate and whose emission wavelength is adjusted by the lattice constant of the compound semiconductor substrate.

Abstract: A first multimode interferometer has a first input port to which an optical signal is applied, a first output port, and a second output port. A first optical waveguide is connected to the first output port of the first multimode interferometer. The first optical waveguide has a refractive index changed in response to a trigger signal externally applied. A second optical waveguide is connected to the second output port. A triggering unit supplies, to the first optical waveguide, the trigger signal for changing the refractive index of the first optical waveguide. An optical switch is provided which can increase the processing speed, can reduce the device size, and is free from dependency on the polarization state of an optical signal.

Abstract: A first multimode interferometer has a first input port to which an optical signal is applied, a first output port, and a second output port. A first optical waveguide is connected to the first output port of the first multimode interferometer. The first optical waveguide has a refractive index changed in response to a trigger signal externally applied. A second optical waveguide is connected to the second output port. A triggering unit supplies, to the first optical waveguide, the trigger signal for changing the refractive index of the first optical waveguide. An optical switch is provided which can increase the processing speed, can reduce the device size, and is free from dependency on the polarization state of an optical signal.

Abstract: An optical-path-superposing-and-separating unit superposes optical paths of two inputted signal lights with each other, and then separate them. A non-linear waveguide is arranged in an area where the optical paths are superposed with each other. First and second optical waveguide are connected to the optical path superposing-and-separating unit. The second optical waveguide has a longer optical path than the first optical waveguide. A control light is introduced to the non-linear waveguide. An interference separator distributes the inputted two signal lights depending on a phase difference therebetween. Third and fourth optical waveguides connect the optical-path-superposing-and-separating unit to the interference separator.

Abstract: An all-optical switch, an all-optical signal waveform reshaping element and an all-optical asymmetric demultiplexer are formed of an optical interferometer having a compact and simple structure. Nonlinear gain media are provided at positions different from each other in two arms of a Mach-Zehnder optical interferometer. Then, an optical cavity is formed by mounting a mirror on an optical input-output port in each of a first and a second multi-mode optical interferometers connected with the two arms. Furthermore, when a saturable absorption medium is placed on the mirror of one of the multi-mode optical interferometers, a mode-locked laser oscillation is induced.

Abstract: An optical-path-superposing-and-separating unit superposes optical paths of two inputted signal lights with each other, and then separate them. A non-linear waveguide is arranged in an area where the optical paths are superposed with each other. First and second optical waveguide are connected to the optical path superposing-and-separating unit. The second optical waveguide has a longer optical path than the first optical waveguide. A control light is introduced to the non-linear waveguide. An interference separator distributes the inputted two signal lights depending on a phase difference therebetween. Third and fourth optical waveguides connect the optical-path-superposing-and-separating unit to the interference separator.

Abstract: A first multimode interferometer has a first input port to which an optical signal is applied, a first output port, and a second output port. A first optical waveguide is connected to the first output port of the first multimode interferometer. The first optical waveguide has a refractive index changed in response to a trigger signal externally applied. A second optical waveguide is connected to the second output port. A triggering unit supplies, to the first optical waveguide, the trigger signal for changing the refractive index of the first optical waveguide. An optical switch is provided which can increase the processing speed, can reduce the device size, and is free from dependency on the polarization state of an optical signal.

Abstract: The present invention relates to a semiconductor device with quantum dots and a method of manufacturing the same, and a structure of the semiconductor device which can control an emission wavelength of the quantum dots and a method of manufacturing the same are provided. The semiconductor device comprises a compound semiconductor substrate containing at least three elements, and quantum dots which are formed on the compound semiconductor substrate and whose emission wavelength is adjusted by the lattice constant of the compound semiconductor substrate.

Abstract: The present invention relates to a semiconductor device with quantum dots and a method of manufacturing the same, and a structure of the semiconductor device which can control an emission wavelength of the quantum dots and a method of manufacturing the same are provided. The semiconductor device comprises a compound semiconductor substrate containing at least three elements, and quantum dots which are formed on the compound semiconductor substrate and whose emission wavelength is adjusted by the lattice constant of the compound semiconductor substrate.

Abstract: A semiconductor device having: an underlie having a semiconductor surface capable of growing thereon single crystal; and a first semiconductor layer, the first semiconductor layer including: a first region of group III-V compound semiconductor epitaxially grown on generally the whole area of the semiconductor surface; and second regions of group III-V compound semiconductor disposed and scattered in the first region, the second region having a different composition ratio of constituent elements from the first region, wherein lattice constants of the first and second regions in no strain state differ from a lattice constant of the semiconductor surface, and a difference between the lattice constant of the second region in no strain state and the lattice constant of the semiconductor surface is greater than a difference between the lattice constant of the first region in no strain state and the lattice constant of the semiconductor surface.

Abstract: A semiconductor device having: an underlie having a semiconductor surface capable of growing thereon single crystal; and a first semiconductor layer, the first semiconductor layer including: a first region of group III-V compound semiconductor epitaxially grown on generally the whole area of the semiconductor surface; and second regions of group III-V compound semiconductor disposed and scattered in the first region, the second region having a different composition ratio of constituent elements from the first region, wherein lattice constants of the first and second regions in no strain state differ from a lattice constant of the semiconductor surface, and a difference between the lattice constant of the second region in no strain state and the lattice constant of the semiconductor surface is greater than a difference between the lattice constant of the first region in no strain state and the lattice constant of the semiconductor surface.