We investigate characteristic fluctuations in multi-quantum well (MQW)-based waveguides whose absorption spectrum experimentally changes as a ∼5nm blue shift when dielectric passivation layers are employed. We theoretically show that the blue shift corresponds to a ∼0.03% compressive strain in the MQW resulting in a group refractive index change (Δn _g ) of ∼−0.01. The estimated Δn _g agrees with an experimentally obtained free spectral range of transmittance of an asymmetric Mach–Zehnder interferometer composed of the MQW structure. The results indicate that our theoretical estimation is an efficient way to evaluate the MQW-based waveguide performance with an external stress.

我们研究了基于多量子阱 (MQW) 的波导中的特征波动，当使用介电钝化层时，其吸收光谱在实验上变化为 ~5nm 蓝移。我们从理论上表明，蓝移对应于 MQW 中约 0.03% 的压缩应变，导致群折射率变化 ( Δn _g ) 为约 -0.01。估计的Δn _g与实验获得的由 MQW 结构组成的非对称马赫-曾德尔干涉仪的透射率自由光谱范围一致。结果表明，我们的理论估计是评估具有外部应力的基于 MQW 的波导性能的有效方法。