Ultra-Compact Low-loss Modified n-adjustable Bends

The integration density of photonic integrated circuits (PICs) is significantly limited by the waveguide bend losses. Reducing waveguide losses by design of the geometry of waveguide bends is important for photonic integrated circuits. Currently, circular bend and Euler bend are the two most common bends used in bending waveguide designs. A modified n -adjustable bend is proposed for ultra-small radius (≤2 μm) by applying the widening width method to n -adjustable bends. Simulations and experiments indicate that the modified n -adjustable bends show excellent performances in bend loss when the radius is 0.5, 1.0, 1.5, and 2.0 μm. In the experiments, the reduction of measured bend loss was from 0.8197 dB/90° (Euler bend) to 0.0689 dB/90° (modified n -adjustable bend) when radius equals 1.0 μm, and from 0.1438 dB/90° (Euler bend) to 0.0167 dB/90° (modified n -adjustable bend) when radius equals 2.0 μm. The modified n -adjustable bends are potential candidates for waveguide components in ultra-compact photonic integrated circuits.