Polarization-Independent, High-Contrast InGaAsP/InGaAsP MQW Waveguide Modulator

In this work we demonstrate the polarization-insensitive operation of a multiple-quantum well electroabsorption modulator based on unstrained InGaAsP/InGaAsP material. Very large and shallow quantum wells were grown and used to generate electroabsorptive behaviour which is due to the merging of two effects, precisely: the quantum confined Stark effect and the Franz-Keldysh effect. Within this scheme TE and TM polarizations behave similarly. High-efficiency performance is reported for wavelengths around 1.55 μm.