Abstract
Phase‐matched optical parametric amplification has been observed for the first time in a guided‐wave structure. In 32‐nm‐long Ti‐diffused LiNbO3 channel waveguides amplification of the 1.15‐μ line of a cw He‐Ne laser and the associated difference‐frequency generation were studied. A gain of up to 75% was achieved for the TE10 (pump)–TM00 (signal, idler) mode combination with a peak pump power of ∼200 W, supplied by a tunable pulsed dye laser. An actual coherence length for the parametric interaction of 25 mm was obtained.