Abstract

To date, parametric fluorescence and oscillation in lithium niobate waveguides have been demonstrated with crystal temperatures above 200°C, using pump wavelengths in the visible region (514 to 615 nm).¹ In these experiments phasematching was achieved using crystal birefringence, imposing the use of the d₃₁ nonlinear coefficient for the parametric interaction. More recently, we reported the use of first-order quasi-phase-matching (QPM),² i.e., periodically inverted crystal domains, with a resultant periodic modulation of the sign of the nonlinear coefficient, which has permitted the generation of parametric fluorescence at ambiant temperature, using an 800 nm pump, and the d₃₃ coefficient of lithium niobate³ which is approximately six times greater than the d₃₁ coefficient. Emission has been observed in the 1.2 to 2.5 micron window of interest for optical fiber communication as well as optical sensors.

© 1994 IEEE