Polarization-independent waveguide modulator using a novel quantum well with mass-dependent width

We propose a novel quantum well (QW) structure with two or four thin barriers inserted in which effective width of the well is mass-dependent. It is very useful for polarization-independent optical modulation. Incorporation of tensile strain is also discussed for further improvement of the polarization insensitivity. Fabrication of a modulator with lattice-matched QW's results in 6-V switching voltage with more than -10-dB extinction (--30 dB maximum) for both TE and TM modes over 29-nm wavelength range. Compared with the quasiparabolic QW, this new quantum well has better fabrication tolerance, wider wavelength range of operation, and higher yield.>