Proposal of InGaAs/InAlAs multiple quantum well Mach–Zehnder modulator integrated with array of planar antennas

Abstract

Abstract We propose an InGaAs/InAlAs multiple quantum well (MQW) Mach–Zehnder modulator integrated with an array of gap-embedded planar antennas for 60 GHz band radio-over-fiber system. The modulator enables us to directly convert from wireless millimeter-wave (MMW) signals to light-wave signals without any connection cables. A newly designed MQW for the modulator exhibits a large refractive index change at low electric field owing to its unique quantum confined Stark effect, which can achieve push-pull driving in modulation without any external electrical power supply. In addition, by introducing a PIN structure to waveguides, an electric field induced in the antena gap can be applied to a core layer of the waveguide efficiently under the irradiation of MMW signals. The modulator with a 2-element array planar antenna can be driven under an MMW power density of 98 W m −2 . We theoretically discuss designs and characteristics of the MQW, planar antenna, and modulator.