Pockels effect and effective phase modulation in Mach–Zehnder modulators constructed by gain quantum well nanostructures

We report an effective phase modulation for transverse magnetic (TM) waves in Mach–Zehnder modulators constructed by gain quantum well nanostructures on the basis of resonantly enhanced Pockels effect. The numerical results show that the optical gain coefficient is very large in the vicinity of the optical communication wavelength, and it is accessible to obtain a very large refractive index change of 10−2 order of magnitude, and a very small voltage–length product for ππ phase shift with Vπ×L0=0.156Vmm at the working wavelength λ=1.55μm by a suitable bias electric field, which is over ten times less than the previous best report. These properties have a great potential for device application in high-performance and high-miniaturization electro-optical switches and phase modulators at the optical communication window.