Microcavity enhanced Stark optical modulator for long-wave infrared

A voltage-tunable microcavity modulator is designed, fabricated and characterized. The device active area comprises a stack of type II metamorphic quantum wells (QW) sandwiched between doped contact layers that also serve as optical mirrors. The device operates in the spectral region of 8–16 μm. The optical transmission of the cavity can be modulated in a range of ∼2% at a wavelength of 9.5 μm by application of a bias voltage with an amplitude of 4 V. The sign of the transmission change depends on the voltage polarity as expected from the first order Stark effect in the polar type-II QWs. This results in a two times higher transmission modulation amplitude at a given voltage compared with type I quantum wells and bulk materials.