Improvement of side-mode suppression ratio of a single-mode SCC semiconductor laser

A new way to improve the single-longitudinal-mode spectrum of short-coupled-cavity (SCC) semiconductor lasers is reported. It is found that an antireflective coating on the end facet of the laser diode in the SCC cavity is necessary for high-quality single-mode operation. Based on the theoretical analyses, a new type of miniature SCC laser has been constructed and demonstrated. Single-mode output with 35¿40 dB side-mode suppression ratio has been obtained under CW and 150 MHz modulation conditions.