Analysis of second harmonic generation in photonic-crystal-assisted waveguides

We study second harmonic generation in a planar dielectric waveguide having alow-index, polymer core layer, bounded by two multilayer stacks. This geometryallows exceptionally strong confinement of the light at the fundamentalwavelength inside the core region with virtually zero net propagation lossesfor distances that exceed several centimeters, provided material and scatteringlosses are neglected. A phase-matched configuration of the waveguide isreported in which the pump signal is the lowest-order mode of the waveguide,and the generated second harmonic signal corresponds to the third propagationmode of the waveguide. Using a polymer waveguide core, having chi(2)=100 pm/V,we predict a conversion efficiency of approximately 90% after a propagationdistance of 2 mm, using peak pump intensities inside the core of the waveguideof 1.35 GW/cm^2. If the waveguide core contains polymer layers with differentglass transition temperatures, the layers can be poled independently tomaximize the overlap integral, and similar pump depletions may be achieved overa distance of approximately 500 microns.Comment: 20 pages, 7 figures, 330k