Junction field-effect transistor single quantum well optical waveguide modulator employing the two-dimensional Moss–Burstein effect

A modulation-doped junction field-effect transistor incorporating an optical waveguide under the gate modulates light by the carrier band-filling effect (two-dimensional Moss–Burstein effect) in a single quantum well, achieving a 5:1 extinction ratio in a 250-μm-long waveguide for 4 V reverse gate-source bias Vgs swing and 0 V drain-source bias Vds. Similar performance is obtained over a 16 nm spectral range. A novel band-edge transparency effect is observed for Vds>0 allowing an extinction ratio of 10:1, corresponding to a change in absorption of 92 cm−1 to be obtained through band-gap dilation by hot electrons at biases of Vds =8 V. Below-band-gap refractive index modulation of 1.6×10−3 is obtained for a Vgs swing of 2.4 V. The novel junction field-effect transistor optical modulator also functions as a photovoltaic or photoconductive optical detector, a transistor, and a light-emitting diode.