Abstract

We designed resonant periodic waveguides for output enhancement of counterpropagating surface normal second harmonic generation (SNSHG). The waveguides consist of alternating λ^(2ω)/ 2 layers of materials with high and low χ⁽²⁾ and n^(2ω) which we refer to as the "generating" and "spacing" layers, respectively. Our model assumes the excited source elements in the generating layers emit SH fields; the same process is weaker in spacing layers that offer proper phase shift to get in phase enhancement at the output surface. We designed Al_0.7Ga_0.3As/Al_0.9Ga_0.1 As waveguides for 532 nm and 475 nm. High Al AlGaAs was used because of the absorption loss of SH fields, especially to blue light. However, nonzero χ⁽²⁾ of spacing layers become the most important loss mechanism. The relative importance of other losses, such as absorption to the SH field and reflection at interfaces determined by admittances at 2ω, was also considered. The samples are currently being grown by MOCVD and available experimental results will be reported.

© 1992 Optical Society of America