Semiconductor laser device having plurality of layers for emitting lights of different wavelengths and method of driving the same.

摘要

A semiconductor laser device capable of emitting lights of different wavelengths has a substrate (1), a first light-emitting layer (11a) provided on the substrate (1), and a second light-emitting layer (11b) provided on the substrate (1) and having a greater band gap than the first light-emitting layer. A barrier layer (12) is disposed between the first and second light-emitting layers (11a, b). The barrier layer (12) has a band gap greater than those of the first (11a) and second (11b) light-emitting layers. The band gap and the thickness of the barrier layer (12) are determined to be large enough to create, in response to injection of carriers to the light-emititng layers, a state in which the carrier density in the second light-emitting layer (11b) is made higher while the carrier density in the first light-emitting layer (11a) is made lower than those which would be obtained when the barrier layer (12) is omitted. The device further has a pair of cladding layers (3, 5) sandwiching therebetween the first light-emitting layer (11a), the barrier layer (12) and the second light-emitting (11b) layer, the cladding layers (3, 5) having smaller refractive index values than the first and second light-emitting layers (11a, b). The device further has electrodes (7, 8) for supplying electrical currents to the first and second light-emitting layers (11a, b).