Parallel string comparison using spatially separated controlled-SWAP gates based on Laguerre-Gaussian modes of light

We demonstrate a parallel optical processing protocol that utilizes spatially separated controlled-SWAP gates based on Laguerre-Gaussian modes. Information is encoded in the relative phase between superposed LG modes within each channel, while the aggregated detection provides channel-independent similarity measurement. We experimentally validate this approach for N=2 and N=3 parallel channels, demonstrating protocol performance across a broad data overlap range (10% to 100%), and verifying channel symmetry. The obtained results show good agreement with theoretical values. This hybrid approach combines spatial multiplexing with phase encoding to enable a computational framework for multiple data streams requiring real-time similarity verification, with scalability constraints related to interferometric complexity and digital micromirror device dimensions.