N-type modulation-doped multi quantum well semiconductor laser device

摘要

An n-type modulation-doped multi quantum well semiconductor laser device having a multi quantum well structure composed of a hetero-junction structure including well layers and barrier layers, characterized in that each of the well layers and each of the barrier layers are formed of an undoped semiconductor material and a semiconductor material modulation-doped with an n-type dopant, respectively, an anti-reflection film and a high-reflection film are formed on the front and rear facets, respectively, the resonator length is not shorter than 800 &mgr;m, and mirror loss (&agr;_m) given by; $PTEXTPDAT\&agr;/PDATHILSBPDATm/PDAT/SB/HILPDAT\=(1/2/PDATHILITALICPDATL/PDAT/ITALIC/HILPDAT)ln\{1/(/PDATHILITALICPDATRf\×Rr/PDAT/ITALIC/HILPDAT)\},/PDAT/PTEXT$ ;where L, Rf and Rr are the cavity length (cm), reflectance of the front facet, and reflectance of the rear facet, respectively, is not higher than 15 cm^−1. The output of this laser device is higher than that of a conventional undoped MQW semiconductor laser device. The device of the present invention, for use as a 1,480 nm laser device for EDFA excitation, for example, is of great industrial value.