Integrated polarization beam splitter based on thin-film lithium niobate waveguide

Abstract

The invention discloses an integrated polarization beam splitter based on a thin-film lithium niobate waveguide. A 1*2 multimode interference coupler, a multistage phase shifter and a 2*2 multimode interference coupler are sequentially cascaded to form a Mach-Zehnder interferometer structure. The 1*2 multimode interference coupler is composed of a first conical waveguide, a second conical waveguide, a third conical waveguide and a multimode waveguide. The 2*2 multimode interference coupler is composed of a first conical waveguide, a second conical waveguide, a third conical waveguide, a fourthconical waveguide and a multimode waveguide. The multi-stage phase shifter is composed of a first interference arm and a second interference arm. The first interference arm is formed by sequentiallyconnecting a first connecting waveguide, a first phase shift waveguide, a second connecting waveguide, a second phase shift waveguide and a third connecting waveguide. The second interference arm is formed by sequentially connecting a fourth connecting waveguide, a third phase shift waveguide, a fifth connecting waveguide, a fourth phase shift waveguide and a sixth connecting waveguide. The integrated polarization beam splitter has the characteristics of high extinction ratio, low loss, simple structure, simple design and simple processing.

Description

technical field [0001] The invention specifically relates to an integrated polarization beam splitter based on thin-film lithium niobate waveguide, which is suitable for optical fiber communication, on-chip optical communication, optical sensing system, and quantum optical system that require polarization beam splitting, polarization combining, and polarization filtering. application occasions. Background technique [0002] Lithium niobate has strong electro-optic effect, strong nonlinear effect and good thermal stability, so it is widely used in integrated optical devices such as electro-optic modulators and wavelength converters. In recent years, with the maturity of thin-film lithium niobate processing and preparation technology, ultra-small integrated optical devices based on thin-film lithium niobate waveguides have developed rapidly. Since the thin-film lithium niobate waveguide has a high refractive index difference and a small mode spot size, this type of waveguide ...

AI Technical Summary

Problems solved by technology

However, lithium niobate is an anisotropic material, and x-cut thin films are usually required to ensure maximum electro-optical modulation efficiency and wavelength conversion efficiency, resulting in different effective refractive indices for thin film lithium niobate waveguides with different transmission directions, This greatly increases the difficulty of designing an asymmetric coupler

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