Reshaping of a second-harmonic curve in periodically poled Ti:LiNbO3 channel waveguide by a local-temperature-control technique

We have demonstrated reshaping and bandwidth control of a second-harmonic (SH) curve in a periodically poled Ti:LiNbO3 (Ti:PPLN) waveguide (Λ=16.6μm) by using a local-temperature-control technique. With this technique, we have achieved several useful shapes of the SH curve such as an almost ideal sinc function, and double and multipeaks in a 74-mm-long Ti:PPLN waveguide, which has a prechirped SH curve at room temperature. More than 60% improvement of SH conversion efficiency and a 5nm broadening of SH phase-matching bandwidth were achieved.