O-Band Fiber-to-Chip Edge Coupler for High NA Fiber Based on a CMOS Compatible SOI Platform

A SiN edge coupler is experimentally demonstrated with
$\mathrm{a} < 1.9$
dB/facet loss over the whole O band for a
$4\mu\mathrm{m}$
MFD fiber. The power is further transformed into Si waveguide using a SiN-to-Si transition.