Reconfigurable and Scalable Multimode Silicon Photonics Switch for Energy-Efficient Mode-Division-Multiplexing Systems

Abstract

A novel integrated scalable multimode switch (SMS) is experimentally demonstrated using tapered multimode-interference-based couplers and Ti/W metal heater phase shifters for mode-division-multiplexing (MDM) silicon photonics switching. The SMS allows path-reconfigurable switching of the first two (TE0 and TE1) or the first three (TE0, TE1, and TE2) transverse electric (TE) modes using the same device achieving footprint efficiency for higher bandwidth density. A proof-of-concept realization of the two-mode switch demonstrates the (de)multiplexing and switching of broadband optical signals over the TE0 and TE1 modes exhibiting $-$ 6.5 dB insertion loss (IL) in the bar state and $-$ 7.3 dB IL in the cross state at 1550 nm with less than $-$ 14 dB crosstalk. Simultaneous switching of two parallel TE modes (TE0+TE1) exhibits less than $-$ 7.0 dB IL and $-$ 11.9 dB crosstalk at 1550 nm. An aggregated bandwidth of 2 × 10 Gb/s is experimentally achieved while switching between two non-return-to-zero PRBS31 data signals with <9.8 $\mu$ s switching time and >17.7 dB switching extinction ratio (ER) for individual-mode transmission, and <7.6 $\mu$ s switching time and >12.0 dB switching ER for dual-mode transmission. The SMS is scalable to switch higher order TE modes with lower energy consumption (up to 63% less) than the single-mode switches indicating its potential application in energy-efficient MDM photonic networks.