Low-loss and broadband arbitrary ratios 1 × 2 power splitter based on asymmetrically tapered multimode interference

Abstract This work presents a low-loss and broadband 1 × 2 power splitter with arbitrary power splitting ratios (PSRs) based on asymmetrically tapered multimode interference. The asymmetrically input tapered waveguide is employed to gradually alter the direction of light propagating in the multimode region. Experimental results show that the device can maintain low losses (∼0.2–0.4 dB) with adjusted PSRs ranging from 50%:50% to 75%:25% at 1550 nm. The adjustable range of PSRs can be extended by increasing the asymmetry of the structure. Additionally, its performance is weakly dependent on wavelength within the range of 1530–1565 nm. Benefiting from the gradual alteration of the direction of light propagation, the device exhibits a low output phase difference of ±8.7°, and the maximum phase deviation is below 6.2° over the wavelength range from 1500 nm to 1600 nm.