Numerical analysis of carrier-depletion InGaAsP optical modulator with lateral PN junction formed on III–V-on-insulator wafer

Abstract

We numerically investigated the modulation characteristics of a carrier-depletion InGaAsP optical modulator with a lateral PN junction fabricated on a III–V-on-insulator (III–V-OI) wafer. Owing to the large electron-induced refractive index change in InGaAsP, the InGaAsP optical modulator with a doping concentration of 2 × 1018 cm−3 in the PN junction exhibited a phase modulation efficiency VπL of 0.17 Vcm, which was 6 times smaller than that of a Si modulator with the same structure. The doping concentration dependence revealed that αVπL, which is a product of the insertion loss α and VπL, can significantly be improved using InGaAsP when the doping concentration was as high as 1 × 1018 cm−3. Thus, we concluded that the phase modulation efficiency and insertion loss can be improved simultaneously using InGaAsP instead of Si for a carrier-depletion optical modulator with a lateral PN junction.