Low-crosstalk penalty MZI space switch with a 0.64-mm phase shifter using quantum-well electrorefraction

We investigate Mach-Zehnder interferometric (MZI) space switches with quantum-well phase shifters. We find that the minimum phase shifter length is limited by additional crosstalk due to electroabsorption-induced imbalance in the MZI. This criterion also provides an optimal detuning between the bandgap and the operating wavelength of the MZI. Finally, we present a novel MZI with an ultrashort 0.64-mm phase shifter.