Compact low-half-wave-voltage thin film lithium niobate electro-optic phase modulator fabricated by photolithography assisted chemo-mechanical etching

TL;DR

This paper introduces a compact, efficient thin film lithium niobate electro-optic phase modulator fabricated via photolithography-assisted chemo-mechanical etching, demonstrating high performance and wavelength insensitivity for optical communications.

Contribution

The paper presents a novel fabrication method for a dual-arm TFLN phase modulator with doubled modulation efficiency and low voltage operation, outperforming conventional designs.

Findings

Half-wave voltage of ~3 V at 1 cm length

Low insertion loss of 2.8 dB

Generation of 29 sidebands at 2 W microwave power

Abstract

This paper presents a compact dual-arm thin film lithium niobate (TFLN) electro-optic phase modulator fabricated using the photolithography-assisted chemo-mechanical etching (PLACE) technique. The design of the device allows for complete utilization of the microwave electric field, doubling the modulation efficiency compared to single-arm modulators in theory. With a half-wave voltage of approximately 3 V and a modulation length of 1 cm, the device outperforms conventional phase modulators. Furthermore, the phase modulator exhibits low sensitivity to optical wavelengths in the range of 1510-1600 nm and offers a low insertion loss of 2.8 dB. The capability to generate multiple sideband signals for optical frequency comb applications is also demonstrated, producing 29 sideband signals at an input microwave power of 2 W.