High Power FBG Stabilized Precision IR Laser Source and Application to Convenient Second Harmonic Generation

A tunable high power single frequency IR laser source in the range of 965-985nm has been developed, with a focus on applications to high precision spectroscopy. A PM (polarization maintaining) single mode fiber coupled laser diode with 500mW output power is stabilized using a narrow linewidth PM-FBG. In this configuration, the laser has inherent short term stability ($<$20 kHz), while long term stability is obtained through feedback (piezo stretching), which enabled precise locking to an external interferometer. The PM fiber gives good polarization stability and the laser has reliable, mode-hop-free operation. This fiber coupled single frequency source is coupled into an single pass PPLN waveguide for frequency doubling. Measured single pass conversion efficiency of 100{\%} per Watt has been obtained, with results on a new nominal 300{\%} per Watt waveguide presented. High power ($>$100 mW input) scaling will be presented. A more efficient but less convenient alternative method using PPKTP in an enhanced build up cavity will also be discussed.