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Journal of Micro/Nanolithography, MEMS, and MOEMS • Open Access

Optical propagation and refraction in silicon complementary metal–oxide–semiconductor structures at 750 nm: toward on-chip optical links and microphotonic systems
Author(s): Kingsley A. Ogudo; Diethelm Schmieder; Daniel Foty; Lukas W. Snyman

Paper Abstract

This paper analyzes the optical propagation and refraction phenomena in various complementary metal–oxide–semiconductor (CMOS) structures at 750 nm wavelength. Operation at these wavelengths offers the potential realizations of small microphotonic systems and micro-opto-electro-mechanical systems (MOEMS) in CMOS integrated circuitry, since Si-based optical sources, waveguides, and silicon (Si) detectors can all be integrated on a single chip. It could also increase the optical coupling efficiencies to external optical fibers. With the help of Monte Carlo and RSoft BeamPROP simulations, we demonstrate achievements with regard to optimizing vertical emission, focusing, refraction, splitting and wave guiding in 0.35 to 1.2 μm CMOS technology at 750 nm wavelength. The material properties, refractive indices, and thicknesses of various CMOS over-layers were incorporated in the simulations and analyses. The analyses show that both Si nitride and Si oxi-nitride offer good viability for developing such waveguides. Effective single-mode wave-guiding with calculated loss characteristics of 0.65  dB⋅cm −1 , with modal dispersion characteristics of less than 0.2  ps⋅cm −1 and with a bandwidth-length product of higher than 100 GHz-cm seems possible. A first iteration realization of an optical link is demonstrated, utilizing specially designed avalanche-based Si-LEDs and a specially designed first iteration CMOS waveguide. Potential applications of avalanche-based Si LEDs into microphotonic systems and MOEMS are furthermore proposed and highlighted.

Paper Details

PDF: 14 pages
J. Micro/Nanolith. 12(1) 013015 doi: 10.1117/1.JMM.12.1.013015
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 12, Issue 1, January 2013
Show Author Affiliations
Kingsley A. Ogudo, Tshwane Univ. of Technology (South Africa)
Diethelm Schmieder, Tshwane Univ. of Technology (South Africa)
Daniel Foty, Gilgamesh Associates, LLC (United States)
Lukas W. Snyman, Tshwane Univ. of Technology (South Africa)

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