Affiliation:
1. South China Normal University, Higher-Education Mega-Center
2. Zhejiang University
Abstract
Thin-film lithium niobate (TFLN) is a promising integrated photonics platform but currently lacks a polarization-insensitive multimode interference (MMI) coupler, a crucial component for polarization-related optical communication applications such as polarization management, polarization-division multiplexing, and polarization-insensitive modulation systems. This paper presents a novel, to the best of our knowledge, approach by rotating the MMI structure on an anisotropic x-cut TFLN at specific angles to compensate for the difference in the beat length between the two polarizations. A polarization-insensitive 1 × 2 MMI coupler is experimentally achieved with measured transmittances of −2.5 to −4 dB for both output ports and polarization modes in the wavelength range of 1520–1580 nm.
Funder
National Natural Science Foundation of China
Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang
Basic and Applied Basic Research Foundation of Guangdong Province
Guangdong Provincial Key Laboratory of Optical Information Materials and Technology