Design methodology for efficient frequency conversion in Bragg reflection lasers

Bragg reflection waveguides are shown to be structures that can enable the integration of a laser and optically nonlinear medium within the same cavity for efficient frequency conversion. An effective and simple method of designing phase-matched laser structures utilizing transfer matrix analysis is described. The structures are first optimized in terms of laser performance and then for enhancement of χ(2) nonlinearity. The method for optimization shows that designing for either optimum laser performance or optimum nonlinear performance can conflict. An efficiency term encompassing the requirements of both the laser and nonlinear element is derived. This serves as a figure of merit that includes parameters relevant to both the laser and the nonlinear device. It is then utilized to optimize the structure for efficient parametric conversion. This figure of merit is extended to examine parametric oscillation in the laser cavity for both singly resonant and doubly resonant configurations. It is found that threshold values of 4 W in a practical device can be obtained. Such power levels are easily obtained by mode locking the pump laser. With reduced propagation loss through etch and design improvement, sub-Watt thresholds can be realized.