High-precision measurement of a propagation loss of single-mode optical waveguides on lithium niobate on insulator

TL;DR

This paper reports the fabrication of single-mode lithium niobate waveguides with a nearly symmetric mode profile and a very low propagation loss of approximately 0.042 dB/cm, achieved through optical patterning and chemo-mechanical polishing.

Contribution

It introduces a high-precision measurement method for assessing propagation loss in LNOI waveguides and demonstrates fabrication of low-loss, single-mode waveguides with symmetric mode profiles.

Findings

Propagation loss of ~0.042 dB/cm measured

Waveguides exhibit symmetric mode profiles of ~2.5 microns

Successful fabrication of single-mode LNOI waveguides

Abstract

We demonstrate fabrication of single-mode optical waveguides on lithium niobate on insulator (LNOI) by optical patterning combined with chemo-mechanical polishing. The fabricated LNOI waveguides have a nearly symmetric mode profile of a mode field size of ~2.5 micron (full-width at half maximum). We develop a high-precision measurement approach by which the single mode waveguides are characterized to have a propagation loss of ~0.042 dB/cm.