Fabrication-tolerant wavelength (de)multiplexer based on cascaded Mach-Zehnder interferometers on silicon-on-insulator

We demonstrate a 4-channel 4.5-nm-spaced WDM (de)multiplexer based on fabrication-tolerant cascaded Mach-Zehnder interferometer configuration. Such unique device design greatly reduces the process-induced spectral shift from 9±4.7 nm to only 0.63± 0.52 nm across the whole wafer, verifying the efficacy of the proposed design methodology for dense WDM applications.