1 August 2005 Design of a modulation-doped SiGe/Si optical modulator integrated in a submicrometer silicon-on-insulator waveguide
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Optical Engineering, 44(8), 084001 (2005). doi:10.1117/1.2032147
Abstract
A SiGe/Si optical modulator based on the free-carrier plasma dispersion effect is presented. A SiGe/Si multilayer structure is included in a p-i-n diode and integrated in a submicrometric silicon-on-insulator (SOI) rib waveguide. A P+ Si layer inserted in the Si barriers provide holes that are confined in the SiGe wells at the equilibrium and can be depleted by applying a reverse bias. This structure offers high-speed phase modulation properties. Numerical simulations are used to design the optical modulator. An optimal structure is defined comprising three 10-nm-thick SiGe layers and four 5-nm-thick P+ Si layers. The predicted refractive index variation is 1.7×10–4 under a –6-V bias voltage, and the associated absorption variation is 3 dB/cm. Intensity modulation is obtained by embedding the active region inside a microinterferometric structure. Using resonant cavities a few hundred micrometers long, a modulation depth larger than 60% is achieved with insertion losses of 12 dB, whereas Mach-Zehnder interferometers of a few millimeters length lead to modulation depths larger than 95% with insertion losses lower than 8 dB.
Delphine Marris, Eric Cassan, Laurent Vivien, Daniel Pascal, Alain Koster, Suzanne Laval, "Design of a modulation-doped SiGe/Si optical modulator integrated in a submicrometer silicon-on-insulator waveguide," Optical Engineering 44(8), 084001 (1 August 2005). http://dx.doi.org/10.1117/1.2032147
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KEYWORDS
Silicon

Modulation

Waveguides

Germanium

Modulators

Absorption

Optical modulators

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