DISTRIBUTED FEEDBACK SEMICONDUCTOR LASER ELEMENT
First Claim
1. A distributed feedback semiconductor laser element, comprising:
- an active layer having a multiple quantum well structure including a plurality of well layers having different thicknesses;
a diffraction grating layer that is optically coupled to the active layer; and
a pair of cladding layers with the active layer and the diffraction grating layer interposed therebetween,wherein when a region that is interposed between the cladding layers is defined as a core layer,the diffraction grating layer includes a layer having a refractive index higher than an average refractive index of the core layer, anda thickness of the well layer increases as a distance from the diffraction grating layer increases.
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Abstract
A DFB laser element includes an active layer 4 having a multiple quantum well structure including a plurality of well layers 4B having different thicknesses, a diffraction grating layer 6 that is optically coupled to the active layer 4, and a pair of cladding layers with the active layer 4 and the diffraction grating layer 6 interposed therebetween. An effective refractive index of the diffraction grating layer 6 is high, and a thickness of the well layer 4B increases as a distance from the diffraction grating layer 6 increases. In this structure, it is possible to reduce dependence on temperature when the DFB semiconductor laser element is miniaturized.
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Citations
10 Claims
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1. A distributed feedback semiconductor laser element, comprising:
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an active layer having a multiple quantum well structure including a plurality of well layers having different thicknesses; a diffraction grating layer that is optically coupled to the active layer; and a pair of cladding layers with the active layer and the diffraction grating layer interposed therebetween, wherein when a region that is interposed between the cladding layers is defined as a core layer, the diffraction grating layer includes a layer having a refractive index higher than an average refractive index of the core layer, and a thickness of the well layer increases as a distance from the diffraction grating layer increases. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A distributed feedback semiconductor laser element, comprising:
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an active layer having a multiple quantum well structure including a plurality of well layers having different materials; a diffraction grating layer that is optically coupled to the active layer; and a pair of cladding layers with the active layer and the diffraction grating layer interposed therebetween, wherein when a region that is interposed between the cladding layers is defined as a core layer, the diffraction grating layer includes a layer having a refractive index higher than an average refractive index of the core layer, and a band gap energy that is defined by a material of the well layers decreases as a distance from the diffraction grating layer increases.
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Specification