Abstract
This article reports on the impact of the induced strain on the polarization anisotropy of a parallel set of electroabsorption intensity modulators on a single InGaAs/InGaAsP wafer chip. The strain build up due to the interdiffusion of atomic species across the quantum well region has been demonstrated experimentally using the gray mask-based quantum well intermixing process followed by an annealing step. A voltage swing of 5 V and an intensity modulation depth of more than
−15
dB
has been measured from these modulators. An interdiffusion process modeling has been developed to investigate the consequence of different interdiffusion ratios between the group III and the group V sublattices on the polarization behavior of these modulators, owing to the strain build up and the refractive index profiles for both transverse electric and transverse magnetic modes. The numerical modeling agrees with the experimental results, which indicates that the degree of intermixing on the group V sublattices is more significant compared to that of group III sublattices, hence causing a strained material system after an intermixing process and thus resulting in with polarization insensitive devices.