Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Stella Chemifa Corporation

Tomoya Satoh

Isao Kidoguchi

Toru Takayama

Koichi Hayakawa

Hiroki Nagai

Hitoshi Sato

Tetsuo Nishida

Takeshi Yokoyama

Kazuhiko Shogami

Shouichi Takasuka

Masatoshi Sasaki

A process for preparing difluorophosphate comprising reacting difluorophosphoric acid with at least one salt, as a raw material, selected from a halide salt, a carbonate, a phosphate, a hydroxide and an oxide of an alkali metal, an alkaline earth metal or an onium in the difluoraphosphoric acid, then separating a precipitate from the difluorophosphoric acid by solid-liquid separation, the precipitate being precipitated by crystallization operation in the difluorophosphoric acid, and removing the difluorophosphoric acid contained in the precipitate by distillation to obtain difluorophosphate.

Method for producing difluorophosphate

A semiconductor light emitting device includes a first conductive clad layer that is group III-V semiconductor mixed crystal, an active layer, and a second conductive clad layer. The second conductive clad layer has a laminated structure of at least three layers including a first layer, a second layer, and a third layer disposed in this order closer to the active layer. The second layer and the third layer are included in a striped ridge, and the second layer is positioned at a skirt of the ridge. The surface of the first layer is a flat part at both sides of the ridge. When Al compositions of the first layer, second layer, and third layer are X1, X2, and X3, respectively, the relation X2&#x3e;X1, X3 is satisfied. When film thicknesses of the first layer, second layer, and third layer are D1, D2, and D3, the relation D2&#x3c;D3 is satisfied.

Semiconductor light emitting device and method for manufacturing same

A semiconductor laser device includes an n-type clad layer, an active layer, and a p-type clad layer having a ridge and wing regions. The wing regions are provided with a first trench present on one side of the ridge and a second trench provided on the other side thereof being interposed therebetween. A reflectivity Rf at a front end face of a resonator, a reflectivity Rr at a rear end face of the resonator, a minimum value Wof a width of the first trench in a region adjacent to the front end face, a minimum value Wof a width of the second trench in the region adjacent to the front end face, a width Wof the first trench at the rear end face, and a width Wof the second trench at the rear end face satisfy Rf&#x3c;Rr, W&#x3c;Wand W&#x3c;WA width Wf of the ridge at the front end face, and a width Wr of the ridge at the rear end face satisfy Wf&#x3e;Wr. The ridge includes a region where a width decreases with distance from the front end side toward the rear end side.

Semiconductor laser device

A semiconductor laser device has a red laser element and an infrared laser element on a substrate. The red laser element has a double hetero structure in which an InGaP-based or AlGaInP-based active layer is interposed between a first conductivity type cladding layer and a second conductivity type cladding layer having a ridge. The infrared laser element has a double hetero structure in which a GaAs-based or AlGaAs-based active layer is interposed between a first conductivity type cladding layer and a second conductivity type cladding layer having a ridge. Provided that a first electrode formed over the second conductivity type cladding layer has a width Win a direction perpendicular to a cavity length direction and a second electrode formed over the second conductivity type cladding layer has a width Win a direction perpendicular to a cavity length direction, the relations of W&#x3e;Wand 80 &#x3bc;m&#x2267;W&#x2267;60 &#x3bc;m are satisfied.

A semiconductor laser devicehaving a ridge stripe structure comprises: an n-type clad layerhaving a protrusion; and an n-type current block layercovering the clad layer, except the upper surface of the protrusion. When the width of the upper surface is W, the distance between front and rear cleavage planes is L, the width of the upper surface at the front cleavage plane is Wf, and the width of the upper surface at the rear cleavage is Wr. In a range where a distance from the front cleavage plane is shorter than or equal to L/2, an area Sc of the upper surface is in a range of L/8&#xd7;(3Wf+Wr)&#x3c;Sc&#x2266;L/2&#xd7;Wf, and W in an arbitrary position in the range is in a range of &#xbd;(Wf+Wr)&#x3c;W&#x2266;Wf.

A first and second semiconductor laser, which comprise buffer layers, cladding layers, quantum well active layers, and cladding layers integrated on the substrate and have a stripe geometry, are integrated on a common substrate, with the quantum well active layers in the vicinity of the cavity facets disordered by impurity diffusion. Relationships &#x3bb;&#x3e;&#x3bb;b&#x3e;&#x3bb;b, and E&#x2266;Eare satisfied, where &#x3bb;and &#x3bb;are defined, respectively, as the emission wavelengths of the active layers of the first and second semiconductor lasers, Eand E, respectively, as the forbidden band energies of the buffer layers of the first and second semiconductor lasers, and &#x3bb;band &#x3bb;brespectively as the wavelengths corresponding to the forbidden band energies of the buffer layers of the first and second semiconductor lasers. The generation of reactive currents flowing through the window portions, which is caused by the intensification of disordering performed for window region formation, can be appropriately suppressed for both types of integrated semiconductor lasers.

Two-wavelength semiconductor laser device and method for fabricating the same

The semiconductor laser device includes first and second light emitting portions each including a first cladding layer, an active layer and a second cladding layer, and each having a stripe structure. The stripe structure of the first light emitting portion has a section having a width changing along a resonator direction and includes a first front end face, and relationships of W&#x2267;W; W&#x3e;W; and (W&#x2212;W)/2L&#x3c;(W&#x2212;W)/2Lhold wherein Wis a width on the first front end face; Wis a width in a position away from the first front end face by a distance L; and Wis a width in a position away from said the front end face by a distance L+L(whereas L+L&#x2266;L). The stripe structure of the second first light emitting portion has a section having a width changing along a resonator direction and includes a second front end face, and relationships of W&#x2267;W; W&#x3e;W; and (W&#x2212;W)/2L&#x3c;(W&#x2212;W)/2Lhold wherein Wis a width on the second front end face; Wis a width in a position away from the second front end face by a distance L(whereas L&#x2260;L); and Wis a width in a position away from the second front end face by a distance L+L.

A semiconductor laser device includes a red-light-emission portion and an infrared-light-emission portion on a single substrate. The red-light-emission portion has a structure in which an AlGaInP-based active layer is sandwiched by a first cladding layer of a first conductivity type having a striped portion and a second cladding layer of a second conductivity type. The infrared-light-emission portion has a structure in which an AlGaAs-based active layer is sandwiched by a third cladding layer of the first conductivity type having a striped portion and a fourth cladding layer of the second conductivity type. The first, second, third, and fourth cladding layers are all made of an AlGaInP-based material. When in these layers, the Al:Ga contents are represented by X-X, X-X, X-X, and X-X, respectively, X&#x2267;Xand X&#x2267;Xare satisfied.

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Osaka, Japan

Tomoya Satoh