A high-speed intersubband modulator based on quantum interference in double quantum wells
2002 (English)In: IEEE Journal of Quantum Electronics, ISSN 0018-9197, Vol. 38, no 2, 178-184 p.Article in journal (Refereed) Published
Calculations on a modulator based on quantum interference in AlGaAs/GaAs asymmetric double quantum wells (QWs) are performed. The modulation of the absorption is based on the anti-crossing behavior of the two lowest states in the coupled wells. At anti-crossing, the oscillator strengths of the transitions from these two lowest states to a higher state are changed in opposite directions. The width of the barrier between the wells should be thick enough to allow a large change in oscillator strength with applied field, yet thin enough so that the absorption peaks of the transitions are resolved. The QWs are designed so that one absorption peak has only a small energy shift for the transition used for modulation while the absorption varies rapidly with the applied voltage. A complete structure including a surface plasmon waveguide is proposed enabling calculations of modal absorption. Parameters important for the performance of the modulator are then determined. An extinction ratio of 10 dB at a wavelength of 8.4 mum is predicted for a device length of 18 mum and a peak-to-peak voltage of 0.9 V. The resistance-capacitance-limited 3-dB bandwidth is 130 GHz. The predicted performance compares very favorably with present interband modulators based on the quantum-confined Stark effect.
Place, publisher, year, edition, pages
2002. Vol. 38, no 2, 178-184 p.
anti-crossing; intersubband transition; optical modulator; quantum interference; quantum well
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-6656DOI: 10.1109/3.980270ISI: 000173483000009OAI: oai:DiVA.org:kth-6656DiVA: diva2:11428
QC 201008232006-12-152006-12-152010-08-23Bibliographically approved