# A Lateral MOS-Capacitor Enabled ITO Mach-Zehnder Modulator for Beam Steering

## TL;DR

This paper demonstrates a novel ITO-based Mach-Zehnder interferometer with a lateral MOS phase shifter in silicon photonics, enabling efficient beam steering for applications like LiDAR and holography.

## Contribution

Introduction of a lateral MOS configuration in ITO Mach-Zehnder modulators for improved electro-optic performance in integrated photonics.

## Key findings

- Efficient phase modulation with VπL = 63 V·μm.
- High-performance optical phased array with narrow beam and side lobe suppression.
- Potential for nanosecond beam steering in various optical systems.

## Abstract

Here, we experimentally demonstrate an Indium Tin Oxide (ITO) Mach-Zehnder interferometer heterogeneously integrated in silicon photonics. The phase shifter section is realized in a novel lateral MOS configuration, which, due to favorable electrostatic overlap, leads to efficient modulation (V{\pi}L = 63 Vum). This is achieved by (i) selecting a strong index changing material (ITO) and (ii) improving the field overlap as verified by the electrostatic field lines. Furthermore, we show that this platform serves as a building block in an endfire silicon photonics optical phased array (OPA) with a half-wavelength pitch within the waveguides with anticipated performance, including narrow main beam lobe (<3{\deg}) and >10 dB suppression of the side lobes, while electrostatically steering the emission profile up to plus/minus 80{\deg}, and if further engineered, can lead not only towards nanosecond-fast beam steering capabilities in LiDAR systems but also in holographic display, free-space optical communications, and optical switches.

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Source: https://tomesphere.com/paper/1907.11131