Stable Single-Longitudinal-Mode Operation over Wide Temperature Range on Semiconductor Lasers with a Short External Cavity

V-channeled Substrate Inner Stripe lasers coupled with a Short External Cavity maintain one single longitudinal mode over wide temperature ranges without mode hopping. Temperature stability is obtained when the thermal shift of the modulated spectrum envelope coincides with that of the longitudinal modes. We enhanced the stability by using a Si submount in place of a Cu submount for the laser. The temperature dependence of the gain maximum is compensated by the small thermal expansion of Si. The laser shows a longitudinal mode locking range of more than 46°C. The data are consistent with theoretical calculations.