Patent application number | Description | Published |
20090046748 | Light-emitting device with precisely tuned and narrowed spectral width of optical output and an optical signal source providing the same - A light-emitting device whose output wavelength is easily variable is disclosed. The device provides a light-generating portion that emits light by the carrier injection and a variable wavelength filter that sets a specific wavelength λr. The variable wavelength filter includes two ring waveguide optical coupled with each other and having optical paths different from each other and at least an electrode to apply an electrical signal to the corresponding ring waveguide. By tuning the specific wavelength λr to the wavelength emitted from the light-generating portion, the output wavelength from the light-emitting device may be narrowed. | 02-19-2009 |
20090092159 | Semiconductor light-emitting device with tunable emission wavelength - The present invention is to provide a semiconductor light-emitting device with a variable output wavelength that reduces the wavelength dependence of the optical output power. The light-emitting device provides an optical cavity defined by a reflective end and a reflector. The gain waveguide and the ring resonator are set within the cavity. The reflector comprises a plurality of gratings each accompanied with an electrode. The periodicity of the refractive index in respective gratings is different from each other. The ring resonator shows a plurality of transmission maxima. The light-emitting device emits light with a wavelength defined by the transmission maxima of the ring resonator and the enhanced reflectivity region adjusted by the bias applied to electrodes of the optical reflector. | 04-09-2009 |
20090145858 | METHOD FOR TREATING WASTE WATER CONTAINING NITRATE ION - A method for treating waste water containing nitrate ion which comprises supplying raw waste water from a tube ( | 06-11-2009 |
20090201964 | Semiconductor laser optical integrated semiconductor device - A semiconductor laser is a distributed feedback semiconductor laser in which the lasing wavelength can be changed, and includes a semiconductor substrate and a semiconductor layer portion provided on the substrate and including first and second active layers and an intermediate layer that optically couples the first active layer and the second active layer. The first active layer, the intermediate layer, and the second active layer are arranged in that order in a predetermined axis direction. The semiconductor laser further includes a diffraction grating that is optically coupled with the first and second active layers of the semiconductor layer portion, a first electrode and a second electrode for injecting carriers into the first active layer and the second active layer, respectively, and a third electrode for supplying the intermediate layer with a current. The grating extends in the predetermined axis direction and has a period that is uniform in the predetermined axis direction. | 08-13-2009 |
20090225796 | Diffraction grating device, laser diode, and wavelength tunable filter - A diffraction grating device includes a substrate with a primary surface having a plurality of grating areas that are periodically arranged with a constant period in a predetermined axis direction, the grating area including a first area and a second area, a diffraction grating structure providing a chirped grating whose pitch monotonically changes along the predetermined axis direction, a core layer that is optically coupled with the diffraction grating structure with a coupling coefficient, a plurality of grating portions including the diffraction grating structure and the core layer, the grating portion including a first portion and second portion that are arranged on the first area and the second area, respectively, of the primary surface and a perturbing layer disposed at the first portion or the second portion. The perturbing layer changes the coupling coefficient between the diffraction grating structure and core layer. A periodical change in the coupling coefficient is formed along the core layer, and this change in the coupling coefficient affects the light propagating through the core layer in the direction of the predetermined axis. | 09-10-2009 |
20090296753 | SEMICONDUCTOR LASER AND OPTICAL INTEGRATED SEMICONDUCTOR DEVICE - A tunable distributed feedback semiconductor laser includes a substrate; an optical waveguide structure disposed on a main surface of the substrate and including an active layer and a diffraction grating, the optical waveguide structure being divided into a first DFB portion, a wavelength-tuning region, and a second DFB portion in that order; a first electrode for injecting carriers into the active layer in the first DFB portion; a second electrode for injecting carriers into the active layer in the second DFB portion; and a third electrode for supplying a wavelength tuning signal to the wavelength-tuning region. The diffraction grating extends over the first DFB portion, the wavelength-tuning region, and the second DFB portion. An optical confinement factor of the wavelength-tuning region is smaller than that of the first and second DFB portions. | 12-03-2009 |
20100185036 | METHOD FOR TREATING RADIOACTIVE LIQUID WASTE AND APPARATUS FOR THE SAME - A method for treating a radioactive liquid waste containing a sodium salt, which includes: feeding a radioactive liquid waste containing at least one of sodium hydroxide, sodium hydrogencarbonate and sodium carbonate to an anode chamber in an electrolytic cell provided with an anode and a cathode on both sides of a permeable membrane, which is selectively permeable to sodium ions, and electrodialyzing the radioactive liquid waste; separating sodium ions permeated through the permeable membrane as sodium hydroxide from the radioactive liquid waste in a cathode chamber; separating a radioactive substance remaining in the anode chamber as a concentrated radioactive liquid waste; and recovering the separated sodium hydroxide and concentrated radioactive liquid waste, respectively. | 07-22-2010 |
20100272133 | WAVELENGTH TUNABLE LASER - A wavelength tunable laser includes a DFB portion including a first optical waveguide provided with a first grating; a DBR portion including a second optical waveguide that is optically coupled to the first optical waveguide and is provided with a plurality of second gratings continuously arranged in a waveguide direction; and a phase shift portion including a third optical waveguide that is optically coupled to the first and second optical waveguides. Each of the second gratings has a grating formation area in which a grating is formed, and a grating phase shift area which shifts the phase of the grating adjacent thereto in the second grating. | 10-28-2010 |
20100296539 | SEMICONDUCTOR LASER AND METHOD FOR MANUFACTURING THE SAME - 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. | 11-25-2010 |
20120230359 | QUANTUM CASCADE LASER - A quantum cascade laser includes a plurality of active layers, each of active layers including a first barrier layer, a first quantum well layer, a second barrier layer, a second quantum well layer, a third barrier layer, a third quantum well layer, and a fourth bather layer provided in this order along a predetermined direction; a plurality of injection layers; and a core layer having the active layers and the injection layers, the active layers and the injection layers being alternately provided along the predetermined direction to form a cascade structure. The first quantum well layer has a film thickness larger than a film thickness of the second quantum well layer. The second quantum well layer has the film thickness larger than a film thickness of the third quantum well layer. In addition, the second barrier layer has a film thickness smaller than a film thickness of the third bather layer. | 09-13-2012 |
20130182736 | QUANTUM CASCADE LASER - A quantum cascade laser includes a substrate having a conductivity type, substrate having a first region, a second region, and a third region; a semiconductor lamination provided on a principal surface of the substrate, the semiconductor lamination including a mesa stripe section provided on the second region, an upper cladding layer having the same conductivity type as the substrate, a first burying layer, and a second burying layer, the mesa stripe section including a core layer; and an electrode provided on the semiconductor lamination. The first and second burying layers are provided on the first and third regions and on both side faces of the mesa stripe section. The upper cladding layer is provided on the mesa stripe section, the first burying layer, and the second burying layer. The first and second burying layers include a first and second semi-insulating semiconductor regions comprised of a semi-insulating semiconductor material. | 07-18-2013 |