1. A semiconductor laser, comprising:
a ridge stripe region having a laminated structure provided with at least a lower cladding layer, an active layer, and an upper cladding layer, and formed on a semiconductor substrate;
a first stripe-side region disposed on both outer sides of the ridge stripe region, provide with a buried layer on the upper cladding layer, having a first thickness from a lower surface of the upper cladding layer to a lower surface of the buried layer, and having a width larger in a middle portion of an oscillator than in a light emitting edge; and
a second stripe-side region disposed on both outer sides of the first stripe-side region at least in a vicinity of the light emitting edge, provided with a buried layer on the upper cladding layer, and having a second thickness from the lower surface of the upper cladding layer to the lower surface of the buried layer, the second thickness being smaller than the first thickness.
2. The semiconductor laser according to claim 1, wherein a width of the first stripe-side region on the light emitting edge is equal to or more than 0.1 \u03bcm and equal to or less than 5 \u03bcm.
3. The semiconductor laser according to claim 1, wherein the active layer includes a quantum well, and crystals of the active layer are intermixed in the vicinity of the light emitting edge to form a window region.
4. The semiconductor laser according to claim 1, wherein the lower cladding layer, the active layer, and the upper cladding layer are formed from (AlxGa1-x)yIn1-yP (0\u2266x\u22661, 0\u2266y\u22661).
5. The semiconductor laser according to claim 1, wherein the upper cladding layer of the laminated structure has first and second cladding layers with an etching stop layer interposed therebetween,
wherein in the first stripe-side region in the middle portion of the oscillator, the second upper cladding layer has a thickness equal to or more than 0.003 \u03bcm, and
wherein in the second stripe-side region in the vicinity of the light emitting edge, the second upper cladding layer is completely removed.
6. The semiconductor laser according to claim 1, wherein the upper cladding layer of the laminated structure has first and second cladding layers with an etching stop layer interposed therebetween,
wherein in the first stripe-side region in the middle portion of the oscillator, the second upper cladding layer is removed up to the etching stop layer, and
wherein in the second stripe-side region in the vicinity of the light emitting edge, the etching stop layer and part or all of the first upper cladding layer are removed.
7. The semiconductor laser according to claim 6, wherein the active layer includes a quantum well,
wherein crystals of the active layer and the etching stop layers are intermixed in the vicinity of the light emitting edge to form a window region, and
wherein in the second stripe-side region, the etching stop layer formed from intermixed crystals in the window region is removed.
8. The semiconductor laser according to claim 1, wherein the upper cladding layer of the laminated structure has first, second, and third upper cladding layers with first and second etching stop layers interposed therebetween,
wherein in the first stripe-side region in the middle portion of the oscillator, the third upper cladding layer is removed up to the second etching stop layer, and
wherein in the second stripe-side region in the vicinity of the light emitting edge, the third upper cladding layer, the second etching stop layer, and the second upper cladding layer are removed.
9. The semiconductor laser as defined in claim 8, wherein the active layer includes a quantum well,
wherein crystals of the active layer, the first etching stop layer, and the second etching stop layer are intermixed in the vicinity of the light emitting edge to form a window region, and
wherein in the second stripe-side region, the second etching stop layer formed from intermixed crystals in the window region is removed.
10. The semiconductor laser according to claim 8, wherein the active layer includes a quantum well,
wherein crystals of the active layer, the first etching stop layer, and the second etching stop layer are intermixed in the vicinity of the light emitting edge to form a window region, and
wherein a thickness of the first etching stop layer is larger than that of the second etching stop layer.
11. A method for manufacturing the semiconductor laser according to claim 5, comprising:
forming the lower cladding layer, the active layer, the first upper cladding layer, the etching stop layer and the second upper cladding layer in this order on the semiconductor substrate to provide the laminated structure;
forming the first stripe-side region by etching the laminated structure on both outer sides of the stripe region so as to leave the second upper cladding layer with a thickness equal to or more than 0.003 \u03bcm; and
forming the second stripe-side region by etching the second upper cladding layer up to the etching stop layer in the vicinity of the light emitting end surface.
12. A method for manufacturing the semiconductor laser according to claim 6, comprising:
forming the lower cladding layer, a lower guide layer, the active layer, an upper guide layer, the first upper cladding layer, the etching stop layer, and the second upper cladding layer in this order on the semiconductor substrate to provide the laminated structure;
forming the first stripe-side region by etching the upper cladding layer of the laminated structure up to the etching stop layer on both outer sides of the stripe region; and
forming the second strip-side region by partially or completely etching the first upper cladding layer in the vicinity of the light emitting edge.
13. A method for manufacturing the semiconductor laser according to claim 8, comprising:
forming the lower cladding layer, a lower guide layer, the active layer, an upper guide layer, the first upper cladding layer, the first etching stop layer, the second upper cladding layer with a thickness equal to or more than 0.003 \u03bcm, the second etching stop layer, and the third upper cladding layer in this order on the semiconductor substrate to provide the laminated structure;
forming the first stripe-side region by etching the third upper cladding layer of the laminated structure up to the second etching stop layer on both outer sides of the stripe region; and
forming the second stripe-side region by etching the second upper cladding layer of the laminated structure up to the first etching stop layer in the vicinity of the light emitting edge.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A desulfurizer comprising a composition comprising amorphous iron oxide hydroxide and an organic binder, wherein the composition comprising amorphous iron oxide hydroxide is prepared according to the following steps:
(1) preparing a ferrous salt solution;
(2) mixing the ferrous salt solution with a carbonate solution, a bicarbonate solution, a carbonate solid, or a bicarbonate solid to form a first mixture, and allowing the first mixture to react to yield a second mixture;
(3) filtering the second mixture to remove generated soluble salt and yield a filter cake; and
(4) charging the filter cake with a gas comprising oxygen to yield the composition comprising the amorphous iron oxide hydroxide.
2. The desulfurizer of claim 1, wherein further comprising an additive.
3. The desulfurizer of claim 1, wherein comprising 88-93 wt. % of the composition comprising amorphous iron oxide hydroxide and 7-12 wt. % of the organic binder.
4. The desulfurizer of claim 2, wherein comprising 88-92 wt. % of the composition comprising amorphous iron oxide hydroxide and 7-11 wt. % of the organic binder, and 1-5 wt. % of the additive.
5. The desulfurizer of claim 1, wherein the organic binder is sodium carboxymethylcellulose, sesbania powder, cellulose powder, or a mixture thereof.
6. The desulfurizer of claim 2, wherein the additive is sawdust powder, rice hull powder, wheat bran powder, or a mixture thereof.
7. The desulfurizer of claim 1, wherein, in step (4), preparing the filter cake obtained after step (3) into suspension, then charging the suspension with air for oxidation, and then filtering and drying the suspension to yield a composition comprising amorphous iron oxide hydroxide.
8. The desulfurizer of claim 1, wherein, in step (4), drying the filter cake obtained after step (3) in the air, and then washing the filter cake with water, filtering and drying the filter cake to yield a composition containing amorphous iron oxide hydroxide.
9. The desulfurizer of claim 1, wherein the pH value of the solution in step (2) is between 7.5 and 8.5 at the end of reaction.
10. The desulfurizer of claim 8, wherein the filter cake constitutes between 5 weight % and 30 weight % of the suspension.
11. The desulfurizer of claim 8, wherein charging the suspension with the gas comprising oxygen until the weight proportion of Fe2+Fet is less than 1%.