3  ×  3 optical switch by exploiting vortex beam emitters based on silicon microrings with superimposed gratings

A silicon-on-insulator microring with three superimposed gratings is proposed and characterized as a device enabling 3×3 optical switching based on orbital angular momentum and wavelength as switching domains. Measurements show penalties with respect to the back-to-back of <1  dB at a bit error rate of 10^-9 for OOK traffic up to 20 Gbaud. Different switch configuration cases are implemented, with measured power penalty variations of less than 0.5 dB at bit error rates of 10^-9. An analysis is also carried out to highlight the dependence of the number of switch ports on the design parameters of the multigrating microring.