Fabrication-Tolerant CWDM (de)Multiplexer Based on Cascaded Mach-Zehnder Interferometers on Silicon-on-Insulator

We demonstrate a cascaded Mach-Zehnder interferometer (MZI) based coarse wavelength division multiplexing (CWDM) (de)multiplexer on silicon-on-insulator with its spectral responses well aligned to the defined wavelength grids and are highly tolerant to the manufacturing linewidth variability. This was achieved by optimizing the waveguide widths and lengths of two arms in every MZI. As-realized CWDM (de)multiplexer exhibits a spectral shift of 0.487 nm, an insertion loss of less than 2.1 dB, and a channel crosstalk of lower than -20 dB, while reference devices fabricated on the same chips suffer from serious spectral shift of 15.4 nm to the shorter wavelength and higher insertion loss/channel crosstalk. The proposed MZI design concept can be applied to all MZI-based photonic devices and related photonic integrated circuits, so this work validates a promising design path towards practical WDM applications on silicon-on-insulator.

Automated summary

This study demonstrates a cascaded MZI-based CWDM (de)multiplexer on silicon-on-insulator that is highly tolerant to manufacturing linewidth variability, with well-aligned spectral responses and excellent performance. The proposed MZI design concept can be applied to various MZI-based photonic devices and integrated circuits.