An ultra-compact 3-db power splitter for three modes based on pixelated meta-structure

An ultra-compact and efficient 3-dB power splitter for mode division multiplexing is proposed and demonstrated experimentally in this letter. The device is realized via pixelated meta-structure with a small footprint of only 4 × 4.5 μm2. The measured results show that the insertion losses and inter-mode crosstalk are lower than 1.5 dB and -15 dB for TE₀, TE₁ and TE₂ modes across the wavelength band of 1530-1570 nm. The measured power imbalance between the two output ports are within 0.35 dB. The tolerances to the fabrication errors and temperature variations are also investigated. The demonstrated three-mode power splitter can directly split the mode multiplexed signals without the need of demultiplexing. Such an integrated functional element helps to significantly increase integration density of photonic integrated circuits.