Spatial and temporal coherence of broad-area lasers with grating feedback

摘要

When a broad-area semiconductor Laser (BAL) is operated near threshold or at moderate current, experimental results show that grating feedback (GF) can destabilize the spatial mode structures even though the frequency bandwidth is actually compressed by a factor of 45. Yet at higher injection currents (>2.5I/I-th), because the free-running BAL already exhibits severe filamentation, GF has little influence on the spatial modes, even though the spectral width continues to be compressed by the same factor. This behavior is suggested by the measurement of intensity noise versus pump current. (C) 1998 Optical Society of America [S0740-3224(98)01709-3]. [References: 17]