摘要
A quasi-phase matching (QPM) structure based on phase correction by inserting a "healing block" (HB) of length d HB into M regular domains of constant length d is proposed to enhance the nonlinear conversion efficiency when the first-order QPM domain length d1 is too short to be reliably fabricated. Second-harmonic conversion efficiency 4.69 times higher than that of a third-order QPM grating has been experimentally demonstrated by using HB-QPM where all the domains are longer than 1.08d 1 . © 2013 Optical Society of America.