Study on the effect of aspect ratio in second harmonic generation efficiency factor of domain inverted QPM grating structure.

The presence of fabrication errors in domain engineered quasi-phase-matching (QPM) device directly affects its performance in a nonlinear optical process. The existence of error in the aspect ratio affects the conversion efficiency factor. In this paper, we theoretically analyzed the effect of aspect ratio errors in QPM device. Further, the effect of duty cycle error and incomplete domain inversion on conversion efficiency is also studied for various grating profiles like under-poled, rectangular, and blazed. Their generalized phase profile equations representing the nonlinear optical coefficient have been derived and their corresponding second harmonic efficiency factors are calculated. [ABSTRACT FROM AUTHOR]