Semiconductor laser
First Claim
1. A semiconductor laser which comprises an active layer, and a p-type SCH layer and an n-type SCH layer which sandwich the active layer from upper and lower sides, wherein the n-type SCH layer comprises a multi-layer structure of 2 or more layers, and this multi-layer structure is constituted so that the band gaps of the respective layers may increase as the multi-layer structure is apart from the active layer, wherein an energy of a bottom of a conduction band of one of the n-type SCH layers is higher than a quasi Fermi level of electrons at room temperature and lower than a quasi Fermi level of the electrons at a high temperature.
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Accused Products
Abstract
A semiconductor laser is herein disclosed which comprises an active layer 21 and SCH layers which sandwich the active layer 21 from upper and lower sides, wherein the SCH layer comprises a multi-layer structure of 2 or more layers 22,24,23,25, and this multi-layer structure is constituted so that the band gaps of the respective layers may increase as the multi-layer structure is apart from the active layer.
7 Citations
20 Claims
- 1. A semiconductor laser which comprises an active layer, and a p-type SCH layer and an n-type SCH layer which sandwich the active layer from upper and lower sides, wherein the n-type SCH layer comprises a multi-layer structure of 2 or more layers, and this multi-layer structure is constituted so that the band gaps of the respective layers may increase as the multi-layer structure is apart from the active layer, wherein an energy of a bottom of a conduction band of one of the n-type SCH layers is higher than a quasi Fermi level of electrons at room temperature and lower than a quasi Fermi level of the electrons at a high temperature.
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6. A semiconductor laser, comprising:
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(a) an active layer; (b) an n-type SCH layer disposed on a first side of the active layer; and (c) a p-type SCH layer disposed on a second side of the active layer opposite to the first side, wherein one of the SCH layers includes at least a first layer and a second layer, the first layer being between the second layer and the active layer and having a bandgap less than a bandgap of the second layer, wherein an energy of a bottom of a conduction band of one of the SCH layers is higher than a quasi Fermi level of electrons at room temperature and lower than a quasi Fermi level of the electrons at a high temperature. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. A semiconductor laser, comprising:
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(a) an active layer; (b) an n-type SCH layer disposed on a first side of the active layer; (c) a p-type SCH layer disposed on a second side of the active layer opposite to the first side; and (d) means for maintaining in the laser a relatively high internal quantum efficiency and a relatively low internal loss as temperature of the laser is increased, wherein an energy of a bottom of a conduction band of one of the SCH layers is higher than a quasi Fermi level of electrons at room temperature and lower than a quasi Fermi level of the electrons at a high temperature. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification