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Proceedings Paper

SiGe metallized stub and plasmonic gap mode electro-absorption modulators
Author(s): Roney Thomas; Zoran Ikonic; Robert W. Kelsall
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Paper Abstract

The performance of an electro-optic modulator based on quantum confined Stark effect in a SiGe filled metal stub, coupled to an underlying Si-waveguide, is investigated using finite element simulations. The transmission of the system is controlled by changing the absorption coefficient of the material filling the stub, which modifies both the power transmitted by the stub itself and the field profile, and hence the coupling of this field into the single-mode output waveguide. An extinction ratio of ~8.5 dB with an insertion loss of ~8.5 dB can be achieved via electro-absorption derived from the quantum confined Stark effect (QCSE), assuming that the stub is filled with Ge/SiGe multiple quantum wells (MQWs) or Ge quantum dots (QDs) in a silicon matrix. With the sub-wavelength dimensions of the device offering low power operation and high switching speeds, the effect is of potential interest for application in silicon platform integrated photonics. Comparison is then made with an alternative class of plasmonic modulators based on metal-gap-dielectric structures, relying on the sensitivity of the gap plasmon mode losses near the mode cutoff to the precise refractive index profile, which can be changed via free carrier accumulation. These devices offer reduced insertion losses and, in contrast to the stub structures, their insertion loss and modulation depth scale with device length.

Paper Details

Date Published: 17 January 2011
PDF: 9 pages
Proc. SPIE 7943, Silicon Photonics VI, 79431A (17 January 2011); doi: 10.1117/12.875622
Show Author Affiliations
Roney Thomas, Univ. of Leeds (United Kingdom)
Zoran Ikonic, Univ. of Leeds (United Kingdom)
Robert W. Kelsall, Univ. of Leeds (United Kingdom)

Published in SPIE Proceedings Vol. 7943:
Silicon Photonics VI
Joel A. Kubby; Graham T. Reed, Editor(s)

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