Supermode-Division-(de)Multiplexing With a Multi-Core Silicon Photonic Bus Waveguide

Flexible mode-channels (de)multiplexing is of great significance for reconfigurable mode-division-(de)multiplexing (MDM) systems. By introducing a multi-core silicon photonic bus waveguide, a supermode-division-(de)multiplexing is proposed and demonstrated in this article. The mode field distributions of the guided-supermodes have a major peak and several minor peaks localized in different sub-cores, showing very different behaviors from that in a regular multimode bus waveguide. By manipulating the width of sub-cores, the target supermode-channel is redistributed at one side of the multi-core bus waveguide so that it can be conveniently added/dropped. Moreover, to show the flexibility of this multi-core bus waveguide, an Euler-bend array for multi-channel propagation is designed. It is shown experimentally that the fabricated supermode-channel add/drop exhibits low excess losses of <0.2 dB, <0.37 dB and <0.55 dB for the TE
_S0
, TE
_S1
and TE
_S2
modes in the wavelength range of 1520–1600 nm, while the inter-mode crosstalks for three-mode channels are all less than −24 dB. For the fabricated Euler-bends, the excess losses are less than 0.12 dB and the inter-mode crosstalks are less than −21 dB for the TE
_S0
-TE
_S2
modes. The proposed scheme is promising for realizing mode-selective multiplexers and has potential for the construction of reconfigurable MDM systems.