Broadband Quasi-Phase Matched Second Harmonic Generator using Taper Waveguide

Quasi-phase matching (QPM)[1] offers many advantages such as no restriction imposed on material, use of the largest SHG tensor component and the fundamental guided modes for obtaining the largest field overlap, and so on. In practice, however, deviations in parameters, e.g., grating period, waveguide width, refractive indices, caused in fabrication process or in operating conditions, reduce the SHG efficiency. It is therefore very important to design SHG devices which are tolerable for fabrication errors and operating conditions. Theoretical analysis has shown that large tolerance can be obtained with chirped grating[2]. In this paper, we propose a simple structure for broadened phase matching and present results of basic theoretical analysis.