Multicore Fiber Link With SiN Integrated Fan-Out and InP Photodiode Array

In this letter, we report a compact on-chip fan-out for multicore fiber (MCF) using a focusing grating coupler array realized with a single-etch silicon nitride on insulator platform. The platform uses 248-nm-deep UV lithography and is therefore suitable for mass fabrication. The compact grating coupler is spaced only by 37 μm to match the pitch of the MCF. The measured fan-out coupling loss is 12 dB with a 3-dB bandwidth of 60 nm for all the channels. The channel crosstalk is lower than 35 dB, which makes this a viable technology for integrated fanout. An MCF link is also demonstrated with a fan-out and a unitraveling-carrier photodiode array. Transmission up to 12 Gbps has been achieved for each of the six channels.