High fidelity CNOT gates in photonic integrated circuits using composite segmented directional couplers

Fuente: arXiv
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Autores principales: Piasetzky, Jonatan, Rotem, Amit, Warshavsky, Yuval, Drori, Yehonatan, Cohen, Khen, Oz, Yaron, Suchowski, Haim
Formato: Preprint
Publicado: 2025
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author Piasetzky, Jonatan
Rotem, Amit
Warshavsky, Yuval
Drori, Yehonatan
Cohen, Khen
Oz, Yaron
Suchowski, Haim
author_facet Piasetzky, Jonatan
Rotem, Amit
Warshavsky, Yuval
Drori, Yehonatan
Cohen, Khen
Oz, Yaron
Suchowski, Haim
contents Integrated photonic circuits are a promising platform for scalable quantum information processing, but their performance is often constrained by component sensitivity to fabrication imperfections. Directional couplers, which are crucial building blocks for integrated quantum logic gates, are particularly prone to such limitations, with strong dependence on geometric and spectral parameters which reduces gate fidelity. Here, we demonstrate that composite segmented directional couplers (CSDC) offer a fabrication-tolerant alternative that enhances gate fidelity without active tuning. We design and fabricate a fully integrated photonic controlled-NOT (CNOT) gate using both uniform and composite coupler variants and compare their performance via simulation, classical characterization, and quantum two-photon interference. The composite design reduces the average error probability by nearly a factor of two and decreases variability fivefold. The residual error is primarily limited by photon indistinguishability. Classical matrix reconstruction confirms improved agreement with the ideal CNOT operation. These results establish CSDCs as compact, passive, and foundry-compatible building blocks for robust scalable quantum photonic circuits.
format Preprint
id arxiv_https___arxiv_org_abs_2509_25505
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle High fidelity CNOT gates in photonic integrated circuits using composite segmented directional couplers
Piasetzky, Jonatan
Rotem, Amit
Warshavsky, Yuval
Drori, Yehonatan
Cohen, Khen
Oz, Yaron
Suchowski, Haim
Optics
Quantum Physics
Integrated photonic circuits are a promising platform for scalable quantum information processing, but their performance is often constrained by component sensitivity to fabrication imperfections. Directional couplers, which are crucial building blocks for integrated quantum logic gates, are particularly prone to such limitations, with strong dependence on geometric and spectral parameters which reduces gate fidelity. Here, we demonstrate that composite segmented directional couplers (CSDC) offer a fabrication-tolerant alternative that enhances gate fidelity without active tuning. We design and fabricate a fully integrated photonic controlled-NOT (CNOT) gate using both uniform and composite coupler variants and compare their performance via simulation, classical characterization, and quantum two-photon interference. The composite design reduces the average error probability by nearly a factor of two and decreases variability fivefold. The residual error is primarily limited by photon indistinguishability. Classical matrix reconstruction confirms improved agreement with the ideal CNOT operation. These results establish CSDCs as compact, passive, and foundry-compatible building blocks for robust scalable quantum photonic circuits.
title High fidelity CNOT gates in photonic integrated circuits using composite segmented directional couplers
topic Optics
Quantum Physics
url https://arxiv.org/abs/2509.25505