Widely tunable 2-micron-band difference frequency generation in direct-bonded quasi-phase-matched LiNbO/sub 3/ ridge waveguide

We fabricate direct-bonded quasi-phase-matched LiNbO/sub 3/ ridge waveguides for 2.3-micron-band difference frequency generation. A 100-nm bandwidth and a 100-%/W conversion efficiency are obtained for the first time using a 0.937-micron pump and a 1.55-micron-band signal.