Anisotropic model for the fabrication of Annealed and Reverse Proton Exchanged waveguides in congruent Lithium Niobate

TL;DR

This paper presents an anisotropic model for fabricating low-loss, high-efficiency waveguides in lithium niobate, accurately predicting device performance and guiding fabrication processes.

Contribution

The study introduces a novel anisotropic diffusion model for proton exchange in lithium niobate, enabling precise fabrication of waveguides with optimized optical properties.

Findings

Propagation losses as low as 0.086 dB/cm

Coupling efficiency of 90% at 1550 nm

Directional coupler splitting ratio prediction within +-0.06

Abstract

An anisotropic model for the fabrication of annealed and reverse proton exchange waveguides in lithium niobate is presented. We characterized the anisotropic diffusion properties of proton exchange, annealing and reverse proton exchange in Z-cut and X-cut substrates using planar waveguides. Using this model we fabricated high quality channel waveguides with propagation losses as low as 0.086 dB/cm and a coupling efficiency with optical fiber of 90% at 1550 nm. The splitting ratio of a set of directional couplers is predicted with an accuracy of +- 0.06.