SEMICONDUCTOR LASER DEVICE AND OPTICAL COMMUNICATION SYSTEM USING IT

摘要

PROBLEM TO BE SOLVED: To provide a beam expander integration type laser diode (BEX-LD) wherein high temperature operation property is ensured and to solve a conventional problem that a usual element structure is difficult to adopt as it is since a beam expander integration type laser diode is prepared on a GaAs substrate and its refractive index is much larger than that of a conventional material if it is constituted to use GaInNAs as an active layer on a GaAs substrate. SOLUTION: This semiconductor laser device has a laser resonator region comprising an active layer region and a clad layer in the upper part of GaAs substrate and a region for expanding a spot diameter of laser beam in an emission surface side of the laser beam. A region for expanding a spot diameter of the laser beam is constituted of a semiconductor material whose lattice constant difference to GaAs is in the range of -0.5% to +0.5%. It is desirable that a main light emission layer in the active layer region consists of GaInNAs. Excellent high temperature operation characteristic of oscillation wavelength of 1.3 μm to 1.55 μm band and high combination efficiency to a proper optical transmission path of a BEX-LD are ensured.