High contrast Fabry–Perot optical modulator using quantum confined Stark effect tuning in InGaAs-GaAs multiple quantum well cavity

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Abstract
Tunable Fabry–Perot modulators, consisting of strained InGaAs-GaAs multiple quantum well (MQW) layers, have been shown to yield a contrast over 1200:1. Tuning is achieved by varying the index of refraction of the MQW layers forming the cavity using a quantum confined Stark effect. The mirrors are realized by AlAs-GaAs quarter wave λ/4 dielectric stacks having 12 and 15.5 periods, respectively. The device has the potential of achieving even higher tunable contrast ratios when the number of periods of the λ/4 mirrors are increased. A contrast ratio of 6000:1 has been achieved for a nontunable structure. Measured data on optical transmission and contrast ratio are presented for various wavelengths as a function of applied bias. Results of simulation of transmitted output are also discussed.