Experimental demonstration of a silicon four-mode (de)multiplexer based on cascaded triple-waveguide couplers

Abstract

Silicon photonics based on-chip mode-division multiplexing (MDM) is an appealing technology for enhancing the interconnect capacity in both short- and long-haul optical communication. Here, a silicon four-mode (de)multiplexer [(De)MUX] is proposed, optimized, fabricated, and characterized for on-chip MDM systems, based on three cascaded triple-waveguide couplers (TWCs), with coupling lengths below 24.25 µm. A four-mode MDM-link consisting of two back-to-back mode-(De)MUXs was fabricated and measured, yielding a crosstalk of less than −15.0dB over a bandwidth wider than 72.6 nm for four modes. In addition, the TWC based mode (De)MUX demonstrates a 1-dB bandwidth greater than 40 nm, and can be considered as a robust component for multimode on-chip networks.