Abstract

Because of their short cavity length, vertical-cavity lasers (VCL’s) typically have only one cavity mode within the gain bandwidth, both of which red shift at different rates with increasing temperature; also, the gain falls off with increasing temperature. Thus, because of ohmic heating with increasing current injection, the VCL output will roll over and eventually cease. Using monolithic lateral photodetectors, we monitor the lateral VCL spontaneous emission and find that the internal light continues to increase with current, even after the output peaks and begins to decrease. When the laser emission ceases, the lateral emission begins to fall, presumably because of the gain decrease. Therefore the VCL maximum output is primarily limited by the cavity mode/gain spectral mismatch and is not due the decrease in gain.

© 1992 Optical Society of America