On-chip mode-division multiplexing link employing bridged subwavelength grating for TM polarization

Mode-division multiplexing (MDM) link that utilizes spatial modes as signal carriers may offer a potentially promising solution for on-chip optical interconnects and communications. Here, an on-chip MDM-link is experimentally demonstrated by employing the bridged subwavelength grating assisted triple-guide coupler. The dispersion of the proposed triple-guide coupler is engineered by introducing the subwavelength metamaterial. The designed MDM-link was fabricated on a standard silicon-photonics platform. Experimental results show insertion losses less than 1.8 dB and crosstalk lower than -21 dB at the center wavelength. The operating bandwidths of TM0 and TM1 modes were measured to be 78 and 100 nm under the crosstalks less than -10 and -17 dB, respectively. The proposed MDM-link may offer a broadband communication for on-chip optical interconnects.