Simultaneous blue and green second harmonic generation in quasiphase matched LiNbO3 waveguide

We report the first simultaneous quasiphase matched second harmonic generation (SHG) of blue (433 nm) and green (532 nm) light in LiNbO3 channel waveguides. Up to 0.45 mW (0.25 mW) of blue (green) light was obtained stimultaneously with an efficiency of 22%/W (28%/W). This result is made possible by using a 6.8 μm period domain inversion grating which serves as a first-order (second-order) grating for green (blue) generation simultaneously. We also show that further enhancement in the SHG performance can be obtained by choosing the appropriate grating depth.