Towards Quantum Networks: Characterizing Raman Noise over Metropolitan-scale Fiber Network

• URL: http://arxiv.org/abs/2607.27970v1
• Date: Thu, 30 Jul 2026 10:17:32 GMT
• Title: Towards Quantum Networks: Characterizing Raman Noise over Metropolitan-scale Fiber Network
• Abstract summary: We analyze Raman scattering in the C-band, used for entanglement distribution, generated by a classical the O-band signal.<n>Our results show that, whenever a quantum signal propagates in the C-band alongside an O-band classical channel within the same fiber, careful selection of the operating frequency is required.
• Score: 3.5240754342877545
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: The coexistence of quantum and classical signals in optical fiber infrastructures represents a major challenge for large-scale quantum networks, as noise sources such as Raman scattering can significantly impact entanglement distribution, and the quantum protocols based on it. In this work, we analyze Raman scattering in the C-band, used for entanglement distribution, generated by a classical the O-band signal. The main contribution of this study lays in investigating these effects in a real metropolitan-fiber network, moving beyond controlled laboratory experiments to deployed telecommunication environments. Measurements are performed over a 7 km metropolitan fiber link using commercial sources and narrowband lasers. The experimental results shows good agreement between the measurements taken under laboratory conditions, although, within the metropolitan-scale loop, localized spectral anomalies are observed in the deployed fibers. Therefore, our results show that, whenever a quantum signal propagates in the C-band alongside an O-band classical channel within the same fiber, careful selection of the operating frequency is required, as Raman scattering and other real-world noise sources can significantly affect the quality and stability of the quantum transmission. In particular, we identify spectral regions that are less affected by Raman noise, thereby providing practical guidelines for optimal quantum channel allocation. We demonstrate that Raman-induced noise constitutes a dominant contribution to the quantum signal-to-noise ratio (SNR) in realistic deployments, beyond background and detector noise. Overall, our findings offer practical insights for deploying quantum communication systems over existing fiber networks, supporting the development of robust and scalable quantum infrastructures.

Related papers

• Engineering Quantum Links: Noise and Quantum-State-Degradation Metrics over Metropolitan Fiber Network [4.376469285036708]
  We build a quantum-network counterparts of the two cornerstone metrics of classical link characterization.<n>On the noise side, we adopt a photon-counting quantum analog of the SINR.<n>On the bit-error side, we consider the main degrees-of-freedom available to encode a quantum state within an optical photon.
  arXiv  Detail & Related papers  (2026-09-10T10:45:42Z)
• Optimization of C-band quantum traffic coexisting with O-band classical traffic: preliminary results [3.734166085697124]
  Coexistence of quantum and classical signals in the same optical fiber is a critical challenge for the deployment of quantum networks.<n>This work experimentally investigates spontaneous Raman scattering (SpRS), a major source of noise in signals transmitted along the same fiber.
  arXiv  Detail & Related papers  (2026-07-29T13:36:16Z)
• Secret Key Rate Limits in Coexisting Classical-Quantum Optical Links [0.0]
  We derive expressions for evaluating the accumulated interference power from coexisting classical signals in a quantum frequency channel.<n>Our model enables effective design of classical-quantum systems in single-mode fibers.
  arXiv  Detail & Related papers  (2026-02-25T08:08:52Z)
• Accurate and Effective Model for Coexistence of Classical and Quantum Signals In Optical Fibers [5.450971469135477]
  We discuss the main interference mechanisms in coexistence scenarios and provide a model to quantify their impact on the quantum signal quality.<n>The model accounts for out-of-band non-linear interference effects, namely spontaneous Raman scattering (SpRS) and four-wave-mixing (FWM)<n>Our model reveals that FWM has negligible impact in counter-propagating schemes, but can be relevant in co-propagating schemes under certain scenarios.
  arXiv  Detail & Related papers  (2025-10-03T08:22:41Z)
• Anticipating Decoherence: a Predictive Framework for Enhancing Coherence in Quantum Emitters [96.41185946460115]
  We develop an anticipatory framework for forecasting and decoherence engineering in remote quantum emitters.<n>We show that a machine learning model trained on limited data can accurately forecast unseen spectral behavior.<n>These results pave the way for real-time decoherence engineering in scalable quantum systems.
  arXiv  Detail & Related papers  (2025-08-04T17:23:14Z)
• Optimizing entanglement distribution via noisy quantum channels [44.99833362998488]
  Entanglement distribution is a crucial problem in quantum information science.<n>We investigate strategies for distributing quantum entanglement between two distant parties through noisy quantum channels.
  arXiv  Detail & Related papers  (2025-06-06T13:48:20Z)
• Purifying quantum-dot light in a coherent frequency interface [39.58317527488534]
  Quantum networks operate in the telecom wavelengths to take advantage of low-loss transmission in optical fibres. Bright quantum dots (QDs) emitting highly indistinguishable quantum states of light, such as InGaAs QDs, often emit photons in the near infrared. We report a method for simultaneously implementing spectral purification and frequency shifting of single photons from QD sources to the C-band in a periodically poled Lithium Niobate waveguide.
  arXiv  Detail & Related papers  (2024-07-11T18:02:43Z)
• Metropolitan-scale Entanglement Distribution with Co-existing Quantum and Classical Signals in a single fiber [0.0]
  Development of prototype metropolitan-scale quantum networks involves transmitting quantum information via deployed optical fibers. One approach addressing these challenges is to co-propagate classical probe signals in the same fiber as the quantum signal. Here, we demonstrate the distribution of polarization entangled quantum signals co-propagating with the White Rabbit Precision Time Protocol (WR-PTP) classical signals in the same single-core fiber strand at metropolitan-scale distances.
  arXiv  Detail & Related papers  (2024-02-01T14:21:39Z)
• Eavesdropper localization for quantum and classical channels via nonlinear scattering [58.720142291102135]
  Quantum key distribution (QKD) offers theoretical security based on the laws of physics. We present a novel approach to eavesdropper location that can be employed in quantum as well as classical channels. We demonstrate that our approach outperforms conventional OTDR in the task of localizing an evanescent outcoupling of 1% with cm precision inside standard optical fibers.
  arXiv  Detail & Related papers  (2023-06-25T21:06:27Z)
• Coexistent quantum channel characterization using spectrally resolved Bayesian quantum process tomography [0.0]
  Coexistence of quantum and classical signals over same optical fiber is critical for operating quantum networks. We systematically characterize the quantum channel that results from simultaneously distributing approximate single-photon polarization-encoded qubits.
  arXiv  Detail & Related papers  (2022-08-30T19:57:45Z)
• Storage and analysis of light-matter entanglement in a fibre-integrated system [48.7576911714538]
  We demonstrate a fiber-integrated quantum memory entangled with a photon at telecommunication wavelength. The storage device is based on a fiber-pigtailed laser written waveguide in a rare-earth doped solid and allows an all-fiber stable adressing of the memory. Our results feature orders of magnitude advances in terms of storage time and efficiency for integrated storage of light-matter entanglement, and constitute a significant step forward towards quantum networks using integrated devices.
  arXiv  Detail & Related papers  (2022-01-10T14:28:04Z)
• Frequency fluctuations of ferromagnetic resonances at milliKelvin temperatures [50.591267188664666]
  Noise is detrimental to device performance, especially for quantum coherent circuits. Recent efforts have demonstrated routes to utilizing magnon systems for quantum technologies, which are based on single magnons to superconducting qubits. Researching the temporal behavior can help to identify the underlying noise sources.
  arXiv  Detail & Related papers  (2021-07-14T08:00:37Z)
• Towards fully-fledged quantum and classical communication over deployed fiber with up-conversion module [47.187609203210705]
  We propose and demonstrate a new method, based on up-conversion assisted receiver, for co-propagating classical light and QKD signals. Our proposal exhibits higher tolerance for noise in comparison to the standard receiver, thus enabling the distribution of secret keys in the condition of 4 dB-higher classical power.
  arXiv  Detail & Related papers  (2021-06-09T13:52:27Z)
• Mid-infrared homodyne balanced detector for quantum light characterization [52.77024349608834]
  We present the characterization of a novel balanced homodyne detector operating in the mid-infrared. We discuss the experimental results with a view to possible applications to quantum technologies, such as free-space quantum communication.
  arXiv  Detail & Related papers  (2021-03-16T11:08:50Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.