Grating Coupler · 1550 nm

This grating coupler is designed on a silicon nitride (SiN) platform for fiber-to-chip coupling at a 1550 nm operating wavelength, with the design optimized to maximize coupling efficiency. The analytic estimate predicts an efficiency of 30.3%, equivalently an insertion loss of 5.183 dB (the same transmission expressed two ways), across a 40.0 nm bandwidth. The grating employs 28 periods with a period of 1.1155 µm and a 0.55 fill factor on a 1 µm waveguide width, with a 100 µm bend radius, occupying a footprint of 182.234 × 13 µm. It achieves a strong fabrication score of 99.0/100, indicating good manufacturability. These figures are analytic estimates rather than results of a physical simulation.