Silicon electro-optical modulator with ITO is smaller and more efficient than existing devices

April 14, 2020
Heterogeneously integrated indium tin oxide thin film in silicon photonics forms a subwavelength-sized plasmonic phase-shifter.

Researchers at the George Washington University (Washington, DC) have developed and demonstrated a silicon-based electro-optical modulator that they say is smaller, as fast as, and more efficient than state-of-the-art technologies.1 By adding indium tin oxide (ITO) -- the transparent conductive oxide commonly found in touchscreen displays and solar cells -- to a silicon photonic chip platform, the researchers were able to create a compact device 1 μm in size and able to yield gigahertz-speed signal modulation.

The new invention is timely, as demand for data services is growing rapidly and moving towards next-generation communications networks. Taking advantage of their compact footprint, electro-optic converters can be utilized as transducers in optical computing hardware such as optical artificial neural networks.

Electro-optical modulators in use today are typically between 1 mm and 1 cm in size. Reducing their size allows increased packaging density, which is vital on a chip. While silicon often serves as the passive structure on which photonic integrated circuits are built, the light/matter interaction of silicon materials induces a rather weak optical index change, requiring a larger device footprint. While resonators could be used to boost this weak electro-optical effect, they narrow devices' optical operating range and incur high energy consumption from required heating elements.

By heterogeneously adding a thin material layer of ITO to the silicon photonic waveguide chip, researchers led by Volker Sorger, an associate professor of electrical and computer engineering, have demonstrated an optical index change 1000 times larger than silicon. Unlike many designs based on resonators, this spectrally broadband device is stable against temperature changes and allows a single fiber-optic cable to carry multiple wavelengths, increasing the amount of data that can move through a system.

Source: https://www.eurekalert.org/pub_releases/2020-04/gwu-bts041320.php

REFERENCE:

1. Rubab Amin et al., Optica (2020); https://doi.org/10.1364/OPTICA.389437.

About the Author

John Wallace | Senior Technical Editor (1998-2022)

John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

Sponsored Recommendations

Achromatic Lenses: High-Quality Custom Optics

March 13, 2025
Ensure clarity and accuracy in your optics systems with Lacroix’s achromatic lenses. Explore how our custom solutions minimize chromatic aberration for perfect results.

Manufacturing Considerations for Tolerancing Aspheres

March 13, 2025
Understand the critical factors in manufacturing aspheres and how Lacroix Optics ensures precise tolerancing in every optical component.

Explore Our Videos: Insights into Precision Optics

March 13, 2025
Get an inside look at Lacroix Optics with our collection of informative videos showcasing our capabilities, innovations, and processes.

Optical Assemblies: Reliable and Precise Solutions

March 13, 2025
Ensure your optical system works seamlessly with Lacroix Optics' custom optical assemblies. Discover the precision and reliability we bring to every project.

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!