Robust Photonic Quantum Gates With A Large Number of Waveguide Segments

Realizing quantum information processors is challenged by errors and noise across all platforms. While composite segmentation schemes are proposed in many systems, their application to photonic quantum gates in dual‐rail configurations has only recently been demonstrated. However, prior research is limited to a small number of segments, full noise correlation, and has overlooked the inherent power loss in such designs. Here, the fidelity and power loss of composite designs for photonic quantum gates with a high number of segments of varying geometrical widths are studied. Using numerical simulations, the relationship between gate performance and the number of waveguide segments, accounting for statistical error correlations and variances is analyzed. Beyond effectively reducing the errors, an asymptotic scaling pattern of quantum gate fidelity and power loss is observed as the number of segments increases. This analysis is examined in Silicon and Lithium Niobate platforms, addressing practical implementation challenges. The findings demonstrate that optimized multi‐segment waveguide geometrical designs significantly enhance the robustness and efficiency of photonic quantum gates, paving the way for more reliable quantum information processors.