Ultra Broadband Tunable Power Splitter Based on Sb₂Se₃-Assisted Y- Junction

1× 2 power splitter is the fundamental component of passive optical network (PON) with bus or ring topology. In existing PON architecture, uplink and downlink wavelengths distribute in a large wavelength range from O-band to L-band, which requires power splitter used in PON having a bandwidth of around 300 nm to cover both uplink and downlink wavelengths. Compared with currently used passive power splitters in ODN, tunable powers can make the network more adaptable to dynamic application requirements. In this work we propose a novel ultra-broadband tunable power splitter based on Sb2Se3-assisted Y- junction. By dividing the subwavelength Sb2Se3 array deposited on the branches into multiple batches and changing the proportion of crystalline Sb2Se3 unit in a batch, the effective refractive indices of branch waveguides are modified. Thus, tunable power splitting ratio from 100%:0% to 50%:50% can be achieved by single device. The device has a compact footprint of 53 × 4 μm2. According to simulation results, at splitting ratio of 100%:0%, the crosstalk and excess loss (EL) are below -14.3 dB and 0.4 dB, respectively in a large bandwidth from 1300 nm to 1600 nm. While at other splitting ratios, the variation of splitting ratio is below ±3.5% and average EL is less than 0.33 dB. The proposed ultra broadband non-volatile tunable power splitter may help increasing the flexibility of PONs.