semiconductor laser

Abstract

Abstract PURPOSE:To inhibit field intensity difference in a resonator and index difference even under the state in which oscillation is grown, to ensure mode selectivity and to obtain an optical output having a stable single wavelength by forming a plurality of and an odd number of phase shifts corresponding to phase difference of 1/2pi to light waves having a Bragg wavelength to the corrugations. CONSTITUTION:With corrugations 4, photo-resists such as a positive resist and a negative resist are applied alternately on the upper surface of an N-type InP clad layer 3 in a striped manner prior to the epitaxial growth of an N-type InGaAsP guide layer 5, and exposed through a two-beam interference method by helium-cadmium (He-Cd) laser beams and a mask is shaped, and phase shifts of 1/2LAMBDA are each formed at the center (1/2L) and positions (S, L-S) at a distance S from respective end surface at a period LAMBDA 200nm corresponding to the order m=1. Where cavity length L=300nm, S=100nm and a coupling coefficient kappa=60cm<-1> are determined, and kappaL=1.8 is decided. Accordingly, even when kappaL of a distributed feedback type laser is large, the mode selectivity of the laser is also ensured after oscillation growth, thus stably acquiring single wavelength beams having a large output.

Inventors

• 👤 Yuji Kotaki
• 👤 小滝　裕二

Bibliographic Details