Semiconductor laser element having a plurality of layers emitting lights of different wavelengths, and its driving method.

摘要

A semiconductor laser element of which oscillation wavelength is variable at a wide range has a high operative efficiency. It comprises a substrate; a first light emitting layer (11a) provided on said substrate and including a resonance cavity, said first light emitting layer (11a) permitting the ground energy level and at least one high-order energy level; a second light emitting layer (11b) provided on said substrate and including a resonance cavity, said second light emitting layer (11b) permitting at least the ground energy level, the band gap of the ground energy level of said second light emitting layer (11b) being wider than that of the ground energy level of said first light emitting layer (11a), and one of the band gaps of the high-order energy levels of the first light emitting layer (11a) being substantially equal to the band gap of the ground energy level of the second light emitting layer (11b); a barrier layer (12) disposed between said first light emitting layer (11a) and said second light emitting layer (11b), said barrier layer (12) having its band gap wider than those of said first and second light emitting layers; a pair of clad layers (13,15) sandwiching therebetween said barrier layer (12) and said first and second light emitting layers (11a,11b), said clad layers (13,15) having lower refractive index than those of said first and second light emitting layers (11a,11b); and electrode means for injecting carrier into said first and second light emitting layers. Also disclosed is a driving method for the semiconductor laser element.