2005/03/17 by J. M. L. Figueiredo, A. R. Boyd, C. R. Stanley +3
Physics and Astronomy · #physics.optics
published as Appl. Phys.Letts, 75, 22, pp. 3443-3445 (Nov. 1999) · 11 pages
arxiv created 2005/03/17 · arxiv updated 2009/12/01
We report electro-absorption modulation of light at around 1550 nm in a unipolar InGaAlAs optical waveguide containing a InGaAs/AlAs double-barrier resonant tunneling diode (DB-RTD). The RTD peak-to-valley transition increases the electric field across the waveguide, which shifts the core material absorption band-edge to longer wavelengths via the Franz-Keldysh effect, thus changing the light-guiding characteristics of the waveguide. Low-frequency characterisation of a device shows modulation up to 28 dB at 1565 nm. When dc biased close to the negative differential conductance (NDC) region, the RTD optical waveguide behaves as an electro-absorption modulator integrated with a wide bandwidth electrical amplifier, offering a potential advantage over conventional pn modulators.