Power-Efficient Silicon Nitride Thermo-Optic Phase Shifters for Visible Light

TL;DR

This paper presents low-power, thermo-optic silicon nitride phase shifters operating in visible wavelengths, achieved through a suspended waveguide design, suitable for integrated photonics applications.

Contribution

The authors demonstrate power-efficient visible-light phase shifters with low power consumption and fast switching times, fabricated using deep ultraviolet lithography on silicon wafers.

Findings

Power consumption for a π phase shift is below 1.3 mW across visible wavelengths.

Devices exhibit approximately 570 μs rise and fall times.

Successful integration into Mach-Zehnder interferometers for switching applications.

Abstract

We demonstrate power-efficient, thermo-optic, silicon nitride waveguide phase shifters for blue, green, and yellow wavelengths. The phase shifters operated with low power consumption due to a suspended structure and multi-pass waveguide design. The devices were fabricated on 200-mm silicon wafers using deep ultraviolet lithography as part of an active visible-light integrated photonics platform. The measured power consumption to achieve a $\pi$ phase shift (averaged over multiple devices) was 0.78, 0.93, 1.09, and 1.20 mW at wavelengths of 445, 488, 532, and 561 nm, respectively. The phase shifters were integrated into Mach-Zehnder interferometer switches, and $10- 90$\% rise(fall) times of about 570(590) $\mu$s were measured.