Title: Gigahertz speed operation of epsilon-near-zero silicon photonic modulators

Abstract

Optical communication systems increasingly require electro-optical modulators that deliver high modulation speeds across a large optical bandwidth with a small device footprint and a CMOS-compatible fabrication process. Although silicon photonic modulators based on transparent conducting oxides (TCOs) have shown promise for delivering on these requirements, modulation speeds to date have been limited. Here, we describe the design, fabrication, and performance of a fast, compact electroabsorption modulator based on TCOs. The modulator works by using bias voltage to increase the carrier density in the conducting oxide, which changes the permittivity and hence optical attenuation by almost 10 dB. Under bias, light is tightly confined to the conducting oxide layer through nonresonant epsilon-near-zero (ENZ) effects, which enable modulation over a broad range of wavelengths in the telecommunications band. Our approach features simple integration with passive silicon waveguides, the use of stable inorganic materials, and the ability to modulate both transverse electric and magnetic polarizations with the same device design. Using a 4-μm-long modulator and a drive voltage of $2{\mathrm{V}}_{pp}$, we demonstrate digital modulation at rates of 2.5 Gb/s. We report broadband operation with a 6.5 dB extinction ratio across the 1530–1590 nm band and a 10 dB insertion loss. This work verifies that high-speed ENZ devices can be created using conducting oxide materials and paves the way for additional technology development that could have a broad impact on future optical communications systems.

Authors:

Wood, Michael G. ;

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• Search DOE PAGES for ORCID "0000-0003-4971-105X"
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Campione, Salvatore ;

• Search DOE PAGES for author "Campione, Salvatore"
• Search DOE PAGES for ORCID "0000-0003-4655-5485"
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Parameswaran, S.; Luk, Ting S.; Wendt, Joel R.; Serkland, Darwin K.; Keeler, Gordon A.

Publication Date:

2018-02-21

Research Org.:

Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); SNL Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1421586

Alternate Identifier(s):

OSTI ID: 1432341

Report Number(s):

SAND2018-0422J
Journal ID: ISSN 2334-2536

Grant/Contract Number:  

NA0003525

Resource Type:

Published Article

Journal Name:

Optica

Additional Journal Information:

Journal Name: Optica Journal Volume: 5 Journal Issue: 3; Journal ID: ISSN 2334-2536

Publisher:

Optical Society of America

Country of Publication:

United States

Language:

English

Subject:

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 47 OTHER INSTRUMENTATION; integrated optics devices; modulators; transparent conductive coatings; atomic layer deposition; electron beam lithography; electrooptical modulators; photonic crystal cavities; thin films; wavelength division multiplexing