用于单模光纤的薄膜铌酸锂平台上的高效宽带偏振不敏感边缘耦合器。

Efficient broadband polarization-insensitive edge coupler on a thin film lithium niobate platform for single-mode fibers.

作者信息

Fang Shaobo, Hong Binzhou, Liu Shuyuan, Lao Yinan, Cai Haiwen, Chu Wei

出版信息

Opt Express. 2025 Apr 21;33(8):18467-18476. doi: 10.1364/OE.561741.

Abstract

We propose a broadband, polarization-insensitive, and fabrication-friendly edge coupler (EC) optimized for efficient coupling between a 600-nm X-cut thin-film lithium niobate (TFLN) platform and a standard 9.2-μm single-mode fiber at 1550 nm. A single-layer silicon nitride (SiN) waveguide structure and a three-stage adiabatic taper are employed to enhance mode-field matching and minimize propagation losses. The optimized EC achieves coupling losses of -0.546/-0.501 dB (TE/TM), polarization-dependent loss (PDL) of 0.035 dB, a 1-dB bandwidth exceeding 100 nm, and robust alignment tolerances (±2.0 μm/±2.2 μm laterally and ±1.7 μm/±1.9 μm vertically for TE/TM modes), making it highly suitable for scalable TFLN photonic integration.

摘要

我们提出了一种宽带、偏振不敏感且易于制造的边缘耦合器（EC），该耦合器针对600纳米X切薄膜铌酸锂（TFLN）平台与标准9.2微米单模光纤在1550纳米处的高效耦合进行了优化。采用单层氮化硅（SiN）波导结构和三级绝热锥度来增强模场匹配并最小化传播损耗。优化后的EC实现了-0.546/-0.501 dB（TE/TM）的耦合损耗、0.035 dB的偏振相关损耗（PDL）、超过100纳米的1分贝带宽以及强大的对准容差（TE/TM模式横向为±2.0微米/±2.2微米，纵向为±1.7微米/±1.9微米），使其非常适合可扩展的TFLN光子集成。