SEMICONDUCTOR LASER DEVICE

摘要

An active layer is provided on a side closer to the second conductivity type cladding layer than a center of the light guide layer in the light guide layer. A first conductivity type low-refractive-index layer is formed between the first conductivity type cladding layer and the light guide layer and has a refractive index which is lower than a refractive index of the first conductivity type cladding layer. A layer thickness d of the light guide layer is a value at which a high-order mode equal to or higher than a first-order mode is permissible in a crystal growing direction by satisfying;2πλng2-nc2d2≧π2.;The active layer is disposed at a position where a light confinement of the active layer becomes smaller compared to a case in which the active layer is disposed at a center of the light guide layer while there is not the first conductivity type low-refractive-index layer.

主权项

1. A semiconductor laser device comprising:
a semiconductor substrate of a first conductivity type; a first conductivity type cladding layer on the semiconductor substrate; a light guide layer on the first conductivity type cladding layer; a second conductivity type cladding layer on the light guide layer; an active layer on a side closer to the second conductivity type cladding layer than a center of the light guide layer in the light guide layer; and a first conductivity type low-refractive-index layer formed between the first conductivity type cladding layer and the light guide layer and having a refractive index which is lower than a refractive index of the first conductivity type cladding layer, wherein λ is an oscillating wavelength of the semiconductor laser device, nc is refractive indexes of the first conductivity type cladding layer and the second conductivity type cladding layer, ng is a refractive index of the light guide layer, a layer thickness d of the light guide layer is a value at which a high-order mode equal to or higher than a first-order mode is permissible in a crystal growing direction by satisfying2πλng2-nc2d2≧π2, and the active layer is disposed at a position where a light confinement of the active layer becomes smaller compared to a case in which the active layer is disposed at a center of the light guide layer while there is not the first conductivity type low-refractive-index layer.