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

We report electroabsorption modulation of light at around 1550 nm in a unip olar InGaAlAs optical waveguide containing an InGaAs/AlAs double-barrier re sonant tunneling diode (RTD). The RTD peak-to-valley transition increases t he electric field across the waveguide, which shifts the core material abso rption band edge to longer wavelengths via the Franz-Keldysh effect, thus c hanging the light-guiding characteristics of the waveguide. Low-frequency c haracterization of a device shows modulation up to 28 dB at 1565 nm. When d c biased close to the negative differential conductance region, the RTD opt ical waveguide behaves as an electroabsorption modulator integrated with a wide bandwidth electrical amplifier, offering a potential advantage over co nventional pn modulators. (C) 1999 American Institute of Physics. [S0003-69 51(99)00748-2].