Title :
Electrooptic Properties of InGaAsP Asymmetric Double Quantum Wells: Enhanced Slope Efficiency in Waveguide Electroabsorption Modulators
Author :
Kim, Dong Kwon ; Citrin, David S.
Author_Institution :
Georgia Inst. of Technol., Atlanta
Abstract :
We present detailed theoretical estimates of the optical properties of InGaAsP quantum well (QW) electroabsorption modulators (EAMs) operating at ~1550 nm wavelength. Absorption coefficients of QWs are obtained from the linear optical susceptibility. Exciton states are calculated in momentum space, which includes valence-band mixing, mixing of excitons originating in different subband pairs, and exciton spin-related optical selection rules. Various line-broadening mechanisms relevant to InGaAsP-QWs are also included. Extending the study further to asymmetric double QWs (ADQWs) suggests that the small-signal modulation efficiency can be enhanced significantly at substantially lower operating bias voltage. Simple optimization of ADQW band structure results in a maximum slope efficiency ~3.8 times larger than that of SQW EAMs at a reduced operating bias field of 34 kV/cm compared with ~70 kV/cm for comparable SQWs.
Keywords :
III-V semiconductors; absorption coefficients; electro-optical modulation; electroabsorption; excitons; gallium arsenide; gallium compounds; indium compounds; optical susceptibility; optical waveguides; quantum interference devices; quantum well devices; semiconductor quantum wells; valence bands; InGaAsP - Interface; absorption coefficients; asymmetric double quantum well; band structure; electrooptic properties; exciton spin-related optical selection rules; excitons mixing; line-broadening mechanisms; linear optical susceptibility; momentum space; operating bias field; operating bias voltage; slope efficiency; small-signal modulation efficiency; subband pairs; valence-band mixing; waveguide electroabsorption modulators; Absorption; Electrooptic modulators; Electrooptical waveguides; Estimation theory; Excitons; Optical mixing; Optical modulation; Optical waveguide theory; Optical waveguides; Quantum mechanics; Analog optical fiber links; asymmetric double quantum wells QWs); electroabsorption modulator (EAM); exciton;
Journal_Title :
Quantum Electronics, IEEE Journal of
DOI :
10.1109/JQE.2007.902783
