Partial Parabolic Single Layer Crossing for Silicon-on-Insulator Nanophotonic Waveguides

Under the dimension of 6 µm overall length, a 220 nm partial parabolic taper fabricated on silicon-on-insulator (SOI) wafer with 2 µm buried oxide at 1.55 µm, to simply fabrication processes and reduce cost, we design a Partial parabolic single layer crossing, which modifies crossing curves around the crossing regions and input-output regions of crossing for fitting the initial input status of the fundamental mode. This single layer crossing for SOI photonic wires which are broadened using a 3 µm partial parabolic taper in each arm to get 97.8% high transmission (−0.097 dB) and −62 dB low crosstalk. It not only can simplify the fabrication processes, reduce cost, and shrink device size to produce more compact photonic circuits, but also keep high transmission over 96.8% even under ±10 nm fabrication dimension variation.