Mid-infrared radiation near 2.8 μm was generated by difference-frequency generation in an 80-mm-long periodically poled Ti:LiNbO<sub>3</sub> channel waveguide by pump radiation near 1.55 μm (tunable external-cavity laser) and a signal radiation of 3.391 μm (HeNe laser). We obtained a normalized conversion efficiency of 105% W<sup>-1</sup> , which is to our knowledge the highest value ever reported.
© 1999 Optical Society of America
(130.3060) Integrated optics : Infrared
(130.3730) Integrated optics : Lithium niobate
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.4390) Nonlinear optics : Nonlinear optics, integrated optics
D. Hofmann, G. Schreiber, C. Haase, H. Herrmann, W. Grundkötter, R. Ricken, and W. Sohler, "Quasi-phase-matched difference-frequency generation in periodically poled Ti:LiNbO3 channel waveguides," Opt. Lett. 24, 896-898 (1999)