Abstract

The spectral linewidth of single-longitudinal-mode injection lasers with tight optical confinement in active regions of a small cross-sectional area, such as the CSP-structure diodes,¹ has been measured as a function of output power. The experimental results presented here show that the linewidths varied linearly with reciprocal mode power in quite accurate fashion, as expected from the Schawlow-Townes² expression for spontaneous phase fluctuations. However, the rate of variation was some 50 times greater than that predicted by the Schawlow-Townes expression without partial inversion.

© 1981 Optical Society of America