# 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.

## Key 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.

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Source: https://tomesphere.com/paper/1907.11188