A novel coupled quantum well with large negative electro-refractive index change and low absorption loss

Abstract

In order to solve excessive insertion loss and low on/off ratio in quantum well reflection-type waveguide optical switches, a novel InGaAs/InAlAs coupled quantum well structure is proposed. In the case of low applied electric field (F=19 kV/cm) and low absorption loss (α ≈61.2 cm−1), a large negative field-induced refractive index change (Δn=−0.0134) is obtained in the novel coupled quantum well structure at the operating wavelength (λ=1550 nm). The value is larger by over one to two order of magnitude compared to that in a rectangular quantum well (RQW) on the above same work conditions.