Efficient four-way vertical coupler array for chip-scale space-division-multiplexing applications.

We propose and demonstrate a three-dimensional nano-printed four-channel vertical coupler array on the silicon-on-insulator platform for efficient chip-to-multicore fiber coupling. The proposed structure provides less than 1 dB loss in a single lane and around 2–4 dB loss in multicore fiber coupling, over 100 nm 1 dB bandwidth, and large 1 dB misalignment tolerances of more than 5 µm in the xy plane and 20 µm in the z direction. The device shows great promise for photonic integrated devices for space-division-multiplexing technology based on multicore fiber.