Modeling of large-bandwidth parametric amplification in the Čerenkov-idler configuration in planar waveguides

Abstract

Parametric amplification in the Cerenkov-idler configuration, in which the pump and the signal fields form guided waves of a planar waveguide while the idler is radiated into the substrate, is analyzed by a coupled-mode approach. Using the quasi-phase-matching scheme for periodically domain-reversed proton-exchanged LiNbO3 waveguides upon a Z-cut substrate, we have shown that this novel configuration has a large signal gain bandwidth and is more tolerant of variations in pump frequency than the all-guided configuration is. One can compensate for the relatively lower gain in the proposed configuration by increasing the interaction length. For typical values of various parameters, numerical results for optimum waveguide parameters (corresponding to maximum signal gain) for a given pump and signal wavelength are presented. Similarly, for a given waveguide the optimum combination of the pump and the signal wavelengths has been estimated. This configuration is expected to find applications in the realization of practical parametric amplifiers and oscillators. © 1997 Optical Society of America.