InGaAs-InP Quantum Wire Stark Effect Modulators: Effect of Wire Width in the Optimization of Changes in Excitonic Absorption and Index of Refraction

Abstract

ABSTRACTQuantum wire/dot modulators offer superior performance over their quantum well counterpart due to enhanced excitonic binding energy. This paper presents simulations on InGaAs-InP quantum wire Stark effect optical modulators showing a novel trend. While the excitonic binding energies and absorption coefficients increase as the width of the wire is decreased, the refractive index change Δn is maximized at a wire width depending on the magnitude of the applied electric field. For example, Δn is maximized at a width of about 100Å for an external electric field of 120kV/cm in an InGaAs quantum wire. This behavior is explained by considering the opposing effects of the wire width on binding energy and changes in the electron-hole overlap function in the presence of an external electric field. Practical InGaAs-InP modulators using V-groove structures are also presented.