COMPARISON BETWEEN DIFFERENCE-FREQUENCY-GENERATION AND PARAMETRIC FLUORESCENCE IN QUASI-PHASE-MATCHED LITHIUM-NIOBATE STRIPE WAVE-GUIDES

Tuning curves and gain are two relevant parameters for integrated opti cal parametric oscillators, We show in this paper that they can be det ermined with a good precision without building a high-finesse cavity b y measurement of the optical parametric fluorescence and difference-fr equency generation. In the first part of this paper, we compare theore tically the guided optical parametric fluorescence and the guided diff erence-frequency generation in the quasi-phase matching configuration. In the second part, we compare experimental results on optical parame tric fluorescence in the 1.2-2.2-mu m region and optical difference-fr equency generation from a 1,55-mu m laser diode using a pump wavelengt h between 775-795 mm in quasi-phase-matched lithium niobate stripe wav eguides. This comparison shows that the gain measured by both methods is identical, but, while parametric fluorescence allows us to obtain t he quasi-phase-matching curve, the difference-frequency generation giv es a simpler and more accurate measurement of the gain, The combinatio n of these two techniques provides therefore a powerful tool for evalu ating the different fabrication processes of the nonlinear waveguides, without actually fabricating a parametric oscillator.