Optical modulation at around 1550 nm in a InGaAlAs optical waveguide containing a InGaAs/AlAs resonant tunnelling diode

Figueiredo, J. M. L.; Boyd, A. R.; Stanley, C. R.; Ironside, C. N.; McMeekin, S. G.; Leite, A. M. P.

Optical modulation at around 1550 nm in a InGaAlAs optical waveguide containing a InGaAs/AlAs resonant tunnelling diode

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Description

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.
11 pages