Abstract

In order to achieve good dynamic single mode operation up to high output powers, distributed feedback (DFB) lasers with a discrete λ/4-shift, multiple phase shifts, and modulated corrugation pitch along the cavity have been considered.^1-3 Haus and Shank have shown⁴ that a discrete λ/4-shift is the optimum way to achieve oscillation at the Bragg position and suppress unwanted modes. However, many groups have attempted to realize a distributed λ/4-shift, and the excellent performance of the corrugationpitch-modulated (CPM) laser² shows that the DFB cavity can indeed be improved by varying the corrugation pitch along the cavity. Thus, the above-threshold performance of DFB lasers with different cavity designs deserves further study.

© 1994 IEEE