Open AccessOptical modulation in silicon waveguides via charge state control of deep levels
Author(s) -
Dylan F. Logan,
P. E. Jessop,
A. P. Knights,
G.J. Wojcik,
Alexander Goebel
Publication year - 2009
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.17.018571
Subject(s) - extinction ratio , materials science , optics , free carrier absorption , silicon on insulator , modulation (music) , absorption (acoustics) , optoelectronics , waveguide , attenuation coefficient , optical modulator , silicon , wavelength , phase modulation , physics , acoustics , phase noise
The control of defect mediated optical absorption at a wavelength of 1550 nm via charge state manipulation is demonstrated using optical absorption measurements of indium doped Silicon-On-Insulator (SOI) rib waveguides. These measurements introduce the potential for modulation of waveguide transmission by using the local depletion and injection of free-carriers to change deep-level occupancy. The extinction ratio and modulating speed are simulated for a proposed device structure. A 'normally-off' depletion modulator is described with an extinction coefficient limited to 5 dB/cm and switching speeds in excess of 1 GHz. For a carrier injection modulator a fourfold enhancement in extinction ratio is provided relative to free carrier absorption alone. This significant improvement in performance is achieved with negligible increase in driving power but slightly degraded switching speed.