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
$4\times 4.5\,\,\mu \text{m}^{2}$
. The measured results show that the insertion losses and inter-mode crosstalk are lower than 1.5 dB and −15 dB for TE
₀
, TE
₁
and TE
₂
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.