Performance analysis of InGaAsP / InP Quantum wire electro absorption modulators

Abstract

Performance of compressively strained (CS) GaInAsP /InP quantum wIre (QWire) electro absorption modulators (EAMs) is theoretically investigated. The electric field dependance of the effective band gap of QWire EAMs (quautum confined Stark effect) is studied using an 8 band k.p theory includiug elastic strain relaxation effects. Elastic strain relaxation is calculatcd using an analytical approach. An empirical relationship is proposed for the effective bandgap for quick and accurate estimation of the Stark shift. The relationship is verified through numerical simulations. Different quantities such as, the absorption coefficient, the extinction ratio and the operating wavelength are calculated as function of device parameters for performance analysis of the QWire EAMs. Polarization in sensitivity is not requiwred to he achieved in the EAMs and the EAMs are designed for absorption of transverse electric (TE) radiation, which is the polarization of light output from QWire lasers fabricated on the same substrate in a photonic int.egrat.ed circuit.. It. is observed that. significant. increase in t.he extinction rat.io can be achieved by adopting QWires in EAMs. In spit.e of higher absorption peaks, Il8.r;.ower wires exhibit. lower ext.inction ratios due to the reduced value of t.he in-plane occupat.ion fact.or. This situation may be improved by increasing the packing densit.y of the QWires. Our result.s are useful for optimizing device design t.hrough proper choice of device parameters t.o meet a cert.a.in requirement.