Liquid crystal mirror-based wavelength-tunable laser module with asynchronous mode cavity

We investigated experimentally the impact of the cavity spacing on the lasing mode stability of the external cavity wavelength-tunable laser (ECTL) with Fabry-Peacuterot etalon and liquid-crystal-based wavelength-tunable mirror. In the asynchronous mode cavity ECTL, the etalon assists in the suppression of the cavity modes at the neighboring transmission peaks of the lasing wavelength due to the misalignment to the etalon's peak. Therefore, the ECTL with asynchronous mode cavity shows highly mode stable lasing operation. The fabricated ECTL module with optimized asynchronous mode cavity shows excellent lasing property of sidemode suppression ratio more than 59 dB and output power of over 14 dBm for a 45-nm tuning range