A semiconductor laser including two laterally coupled waveguides, in which one of the waveguides includes a partially reflecting surface (an internal mirror) between its facets, is analyzed. The internal mirror inserts longitudinal coupling into the system. The spectrum of the Fabry–Perot modes exhibits modulation in the gain required for lasing threshold, with a periodicity that depends on the longitudinal position of the internal mirror. The combined coupled-cavity effect may explain the observed gain spectrum in GaN lasers.
© 2003 Optical Society of America
Orit Skorka and Joseph Salzman, "Lateral and longitudinal coupled waveguides in semiconductor lasers," Opt. Lett. 28, 1939-1941 (2003)