Design of a hybrid mode and wavelength division (de)multiplexer based on contra-directional grating assisted couplers on the SOI platform

This paper presents a hybrid mode and wavelength division (de)multiplexer (MDM-WDM), based on the silicon-on-insulator platform using the grating assisted contra-directional coupling principle. The proposed hybrid MDM-WDM is able to (de)multiplex six channels with two wavelengths and three modes. The proposed device is designed by cascading three grating assisted coupler sections. Each coupler section is dedicated to reflecting a specific mode at two wavelengths. The operation of the proposed design is simulated by the 2.5D finite-difference time-domain technique. The analysis shows that the proposed device structure exhibits an insertion loss of < 0.55 d B , return loss of > 12.81 d B , extinction ratio of > 15.49 d B , and crosstalk of < − 12.74 d B . A fabrication tolerance study for the MDM-WDM device is also performed by changing the inter waveguide distance between the respective multimode bus waveguide and the single-mode waveguide.