Experimental Realization of Broadband Mode-Splitting Using Bridged Subwavelength Grating

On-chip mode-division multiplexing (MDM) holds great promise to tackle a bandwidth crunch for optical communications and interconnects. Here, we experimentally demonstrate the mode-splitting by taking advantage of metamaterial engineering of bridged subwavelength gratings (BSWGs). The proposed mode-splitting consists of a BSWG based mode splitter, a mode multiplexer, and a mode demultiplexer. The designed device was fabricated using CMOS-compatible processes. Our fabricated device exhibits insertion losses of 0.99 and 1.8 dB in the case of manipulation of fundamental and first-order modes. The corresponding mode-crosstalks were tested to be −21.8 and −22.1 dB. The operating bandwidths were measured to be 84 and 100 nm with the mode crosstalk less than −15 dB. The proposed mode-splitting can be implemented as a promising candidate of mode manipulations for an MDM system.