Broadband-signal wavelength converter with high damage resistance.

Uniform MgO-doped near-stoichiometric LiNbO(3) was successfully grown from Li-rich melts by a melt supplying technique. Periodically poled domains were demonstrated in MgO-doped near-stoichiometric LiNbO(3) wafers. Efficient quasi-phase-matched difference frequency generation was achieved in a titanium-diffusion waveguide based on periodically poled MgO-doped near-stoichiometric LiNbO(3). The conversion efficiency was -7.3 dB with a pump power of 150 mW and a signal power of 50 mW at room temperature. It was found that the 3 dB signal conversion bandwidth was as large as 78 nm. Photorefractive damage of the device was examined by pump-probe second-harmonic generation at room temperature, and the device exhibited no significant wavelength shift.