Hetero-nipi band filling modulator with laterally interdigital contacts made by shadow mask molecular beam epitaxy regrowth

An AlGaAs/GaAs optical hetero-nipi modulator based on band filling effect with interdigital selective contacts has been fabricated by use of shadow mask molecular beam epitaxy (MBE) regrowth technique. There is a five order of magnitude change in I-V characteristics from forward to reverse junction bias, which indicates the high quality of the interdigital contacts. The measured reflectance spectra show a change of the absorption coefficient of about 7850 cm−1 with an applied bias voltage as low as 1.5 V.