Calculation of the mode suppression ratio in Fabry-Perot, DBR, and external cavity lasers

摘要

The mode-suppression ratio of Fabry-Perot, distributed Bragg reflector, and external-cavity lasers, both with and without gratings, is calculated using a linear amplifier mode. It is shown that the apparently anomalous behavior of long external cavity structures can be explained using this simple model, provided that the dependence of the spontaneous emission factor on longitudinal mode spacing is included. Practical expressions relating the static mode suppression ratio to laser device parameters are given.