In this contribution, we investigate second harmonic generation (SHG) in periodically poled lithium niobate (LN) on insulator waveguides and examine under what conditions such waveguides suffer from undesirable loss due to lateral leakage. We investigate the lateral leakage losses in X-cut and Z-cut LN for the fundamental (1550 nm) and second harmonic (775 nm) wavelengths. Our findings show that Z-cut lithium niobate on insulator (LNOI) is more likely to suffer from lateral leakage and has a lower SHG efficiency. We further provide design guidelines for highly efficient nonlinear optical waveguides in LNOI and show how lateral leakage can be avoided.

在此贡献中，我们研究了绝缘子波导上周期性极化的铌酸锂（LN）中的二次谐波产生（SHG），并研究了在何种条件下此类波导遭受因侧向泄漏而造成的不良损耗。我们针对基波波长（1550 nm）和二次谐波（775 nm），研究了X形和Z形LN的横向泄漏损耗。我们的发现表明，绝缘子上的Z切铌酸锂（LNOI）更有可能遭受横向泄漏，SHG效率较低。我们进一步为LNOI中的高效非线性光波导提供了设计指南，并说明了如何避免横向泄漏。