Narrow Linewidth Long Wavelength Phase-Locked Laser Array with Mode Controlling Grating Filter

Abstract

Single-longitudinal-mode (DSM) semiconductor lasers have been widely investigated for achieving low chirping and narrow linewidth characteristics. Various schemes such as corrugation-pitch-modulated distributed feedback lasers1, DBR2 or DR3 lasers with passive regions and quantum wire or box lasers with small α parameter4 have been reported. High power and small spontaneous emission factor further reduce the spectral linewidth. For achieving high power and small spontaneous emission factor, phase-locked laser arrays5,6 are attractive as well as for narrow beam operation. We report in this paper a single mode and narrow linewidth characteristics of a five-element 1.5μm GaInAsP/InP phase-locked laser array with a mode controlling grating filter (GFA).