Pith. sign in

REVIEW 5 minor 91 references

Spectral filtering of photon-pair sources degrades the maximum achievable coincidence-to-accidental ratio, and the coincidence rate at which it is reached, in direct proportion to the pair-symmetric heralding efficiency; raising pump power

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗

T0 review · deepseek-v4-flash

2026-08-04 11:08 UTC pith:CEYPBBQ3

load-bearing objection A solid, honest experimental paper with a useful design rule—imperfect filter heralding efficiency directly limits the maximum CAR—but the headline mW-level tolerance is an extrapolation and the quantitative scaling rests on an assumption the authors themselves defer.

arxiv 2510.06536 v1 pith:CEYPBBQ3 submitted 2025-10-08 quant-ph

Optimal filtering and generation of entangled photons for quantum applications in the presence of noise

Jordan M. Thomas , Andrew R. Cameron , Akil Pathiranage , Si Xie , Raju Valivarthi , Panagiotis Spentzouris , Maria Spiropulu , Cristi\'an Pe\~na
show 1 more author
Prem Kumar
This is my paper
classification quant-ph
keywords photon-pair filteringpair-symmetric heralding efficiencycoincidence-to-accidental ratiotime-bin entanglementquantum-classical coexistencespontaneous Raman scatteringmultipair emissionquantum networks
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper asks what filtering does to photon-pair sources that are used for entanglement and interference applications, not just to single-photon detectors. It shows that filtering the joint spectrum of a pair lowers the pair-symmetric heralding efficiency (PSHE), the fraction of detected signal/idler photons that arrive with a partner at the other detector. The central result is a closed-form expression: the maximum coincidence-to-accidental ratio, and the coincidence rate at which it is reached, both scale linearly with PSHE, so an imperfect filter heralding efficiency makes a system more susceptible to any noise that is independent of filter bandwidth. This matters because spectral filtering is standard in quantum teleportation, entanglement swapping, high-rate pulsed sources, and quantum networking, where rate and fidelity are both at stake.

Core claim

The paper's central claim is that after a photon-pair source is filtered, all two-photon performance measures are controlled by the pair-symmetric heralding efficiency δ_PS = sqrt(δ_s δ_i), where each δ_j = μ_both/μ_i/s is the fraction of detected singles that can form true coincidences. Maximizing the coincidence-to-accidental ratio over pump power gives CAR_max = δ_PS sqrt(η_s η_i D_s D_i) / [2 D_s D_i + δ_PS sqrt(D_s D_i/(η_s η_i)) (η_s D_i/δ_i + η_i D_s/δ_s) + 1], reached at μ_both^opt = δ_PS sqrt(D_s D_i/(η_s η_i)). In words, the best possible CAR and the coincidence rate at which it is reached are both directly proportional to δ_PS. An imperfect FHE therefore makes a system more suscep

What carries the argument

The central object is the pair-symmetric heralding efficiency (PSHE), δ_PS = sqrt(δ_s δ_i), where δ_s and δ_i are the filter heralding efficiencies for signal and idler photons: the probability that a detected single has a partner passing the other filter. It is computed from the filtered joint spectral amplitude through μ_s, μ_i, and μ_both. It carries the argument because it appears as a linear prefactor in the maximum-CAR expression Eq. (7) and in the optimal μ_both, converting an abstract filtering trade-off into a single measurable number.

Load-bearing premise

The whole formula hangs on the assumption that accidental coincidences are exactly the product of the two single-count rates after filtering; if spectral correlations survive among photons that pass only one of the two filters, the maximum-CAR expression changes.

What would settle it

An experiment that measures CAR versus pump power for a source with a known PSHE of about 0.2, holding the noise count rate fixed: Eq. (7) predicts both the maximum CAR and the μ_both at which it occurs fall to roughly 20% of their δ_PS=1 values. Measuring a different ratio would falsify the claim. A second check is comparing measured accidentals to S_s S_i in the high-gain or multimode regime.

Watch this falsifier. Get emailed when new claim-graph text bears on it.

Share X Bluesky LinkedIn Reddit HN

If this is right

  • Narrowing filters to reject noise or increase spectral purity lowers PSHE; in the simulated system CAR turns downward below roughly 50 pm even though single-detector signal-to-noise keeps improving, because multipair emission at non-overlap frequencies dominates.
  • Increasing pump power is not a remedy: the optimal mean pair number μ_both is proportional to δ_PS, so systems with imperfect PSHE must cut pump power to reach their (lower) maximum CAR, reducing the true coincidence rate further.
  • Flat-top filters outperform Gaussian filters in both noisy and noise-free conditions, giving higher CAR and higher CAR for a given spectral purity, which matters for N>2-photon applications.
  • Shorter pump pulses broaden the unfiltered joint spectrum, making the FHE drop at wider filter bandwidths; pump-pulse width, filter bandwidth, and filter shape must be co-designed.
  • Experimentally, time-bin entangled photons at 1536.5 nm can co-propagate with 10-Gbps C-band classical data over 25 km/25 km of fiber, tolerating mW-level classical power; simulations with ideal PSHE and source loss suggest roughly 10 dBm launch power could be tolerated.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • If Eq. (7) holds for generic D_j, the same linear PSHE penalty applies to noise sources the paper did not test directly — free-space ambient light, frequency-converter noise, switch leakage, and detector dark counts — making PSHE a universal receiver figure of merit rather than a Raman-specific one.
  • The paper notes that N-fold coincidences would scale roughly as δ_PS^(N/2); an editor-level extrapolation is that PSHE becomes a first-order design parameter for photonic quantum computing and teleportation, where N≥3, not just for two-photon networking.
  • The low-gain, independent-accidental model leaves an open test: a multimode or high-gain filtered source could check whether measured accidentals equal S_s S_i, and if correlations among 'lost' photons appear, Eq. (7) would need a corrected prefactor.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

0 major / 5 minor

Summary. The paper studies how spectral filtering of SPDC photon pairs affects two-photon performance in noisy environments, with emphasis on the filter heralding efficiency (FHE) and the pair-symmetric heralding efficiency (PSHE). The authors define filtered mean photon numbers μ_s, μ_i, μ_both and derive a low-gain model for singles, coincidences, and CAR. The central theoretical result is Eq. (7): after optimizing the pair-generation probability, the maximum CAR and the optimal μ_both are proportional to δ_PS. The paper reports a direct experimental check: at fixed ΔλΔT, hence fixed single-detector SNR, narrower filtering with lower δ_PS reduces the measured CAR maximum (≈155 for 300 pm/300 ps vs ≈40 for 50 pm/1800 ps). It also demonstrates 1536.5-nm time-bin entanglement coexisting with 10-Gbps C-band classical data over 25 km + 25 km fiber, tolerating near-mW C-band launch powers, and uses simulations to analyze filter shape, pump-pulse duration, spectral purity, and the trade-offs for teleportation-type applications.

Significance. If the central result holds, the paper gives a useful quantitative design rule: for a fixed noise floor, an imperfect FHE lowers both the achievable CAR and the optimal generation rate, and increasing pump power cannot compensate. The closed-form expression for CAR_max is valuable, and the experimental design controlling single-detector SNR while varying δ_PS is a clean test of the concept. The C-band time-bin entanglement result with co-propagating classical data is a significant experimental advance. The paper is also transparent about its modeling assumptions: Appendix B explicitly states that the Poissonian low-gain approximation is used and that a full multimode high-gain analysis is deferred. The main text should carry that caveat wherever Eq. (7) is presented.

minor comments (5)
  1. [Section IV, Eq. (7) and Appendix B] The derivation of Eq. (7) uses the low-gain, Poissonian accidentals assumption A=S_s S_i (Eq. B9) and the identities μ_{i/s}=μ_both/δ_{s/i}. Appendix B explicitly says a full multimode/high-gain analysis is left to future work. This is acceptable for the low-gain regime studied here, but Section IV should state this scope condition directly at the point where Eq. (7) is introduced; otherwise the sentence 'maximum fidelity and μ_opt_both are both directly related to the PSHE' reads as a general result. In addition, the optimization leading to Eq. (7) requires D_s,D_i>0: in a truly noise-free system CAR→∞ as μ_both→0 and no finite maximizer exists. Please add these validity conditions.
  2. [Figs. 2(c), 3, and 4(b)] The key quantitative comparisons are shown without error bars. The qualitative conclusion of Fig. 2(c) is robust (peak CAR 155 vs 40), but a quantitative validation of Eq. (7) needs propagated uncertainties. The model curves also appear to use δ_j(Δλ) and noise parameters estimated from the same source and datasets; please state explicitly which quantities are fixed from independent measurements and which are fitted, and consider showing uncertainty bands on the model curves.
  3. [Fig. 2(c) caption] The caption refers to 'the same single-detector SNR (purple)', but no purple curve or marker is described in the text or visible in the panel. Please identify the purple element or remove the reference.
  4. [Section IV terminology] The text states that 'maximum fidelity and μ_opt_both are both directly related to the PSHE', but the quantity actually maximized is the CAR, not an entanglement fidelity. CAR is a coincidence-to-accidental ratio; the connection to visibility or fidelity is model dependent. Please use precise terminology or define the mapping used.
  5. [Eqs. (3)-(4) and Appendix B notation] The symbols S_j and C are called 'count probabilities per gate' in some places and 'count rates' in others. Please define units consistently, since the noise terms R_j Δλ_j ΔT_j and dark-count terms d_j ΔT_j are dimensionless per-gate probabilities only after multiplication by the appropriate duty factors.

Circularity Check

0 steps flagged

No significant circularity: Eq. (7) is an explicit optimization of a stated rate-equation model, with δ_PS as an independently measured input rather than a fitted output.

full rationale

The derivation is self-contained in the paper's own algebra. Appendix B defines μs, μi, μboth via JSA filter overlaps (Eqs. B4-B5), adopts the standard Poissonian/independent-counts accidentals model A=SsSi (Eq. B9), substitutes μi/s=μboth/δs/i, and optimizes CAR with respect to μboth, producing μ_opt_both and CARmax (Eqs. B12-B13; Eq. 7). The δ_PS scaling is a mathematical consequence of those stated assumptions, not a renaming of the conclusion. δ_PS is defined from JSA-filter overlap ratios (δs/i=μboth/μi/s) and is measured/input, while CARmax is a predicted observable, so the claim is not equivalent to its input by construction. The paper transparently flags the key assumption—'we build on this approximation and leave a full multimode analysis in the high-gain regime to future work' (Appendix B)—so the multimode caveat is a validity/scope limitation, not a hidden circular import. Self-citations (e.g., ref. [60]) are used as building blocks, but the load-bearing optimization is performed explicitly in the paper; no uniqueness theorem or prior authors-only result is invoked to force the conclusion. Thus the central claim has independent content, and any concern about the Poissonian accidentals ansatz is a correctness or generality risk, not circularity.

Axiom & Free-Parameter Ledger

3 free parameters · 5 axioms · 0 invented entities

No new particles, forces, or physical entities are introduced. The free parameters are experimentally measured quantities (µ, δ, R) that are necessary inputs to the rate-equation model, not ad hoc constants tuned to force agreement. The main axioms are standard low-gain SPDC modeling assumptions and the specific Poissonian-accidental coincidence model that the paper's central formula depends on.

free parameters (3)
  • µ_T (total pair generation probability per pulse) = µ_s≈1.0e-3, µ_i≈1.1e-3, µ_both≈2.5e-4 (time-bin run)
    Estimated from measured singles and CAR; enters Eqs. (1)-(4) as the source-intensity scale for the experiment and simulations.
  • δ_s, δ_i (filter heralding efficiencies) = δ_s=0.23, δ_i=0.21 in time-bin experiment; δ_PS≈0.22; varies with Δλ as in Fig. 2(b)
    Measured and used as input to predict CAR and visibility; central parameter in Eq. (7).
  • R_s, R_i (SpRS spectral noise densities) = 1477.4 and 1040.1 counts/pm/s at P0=-12.5 dBm; 145793.8 and 158694.0 counts/s/mW in time-bin experiment
    Measured background rates entering D_j = (η_r α_pol R_j Δλ_j + d_j) ΔT_j.
axioms (5)
  • domain assumption Low-gain TMSV photon statistics; multipair emission approximated as Poissonian when µ << 1.
    Appendix B invokes refs. [77-79,88]; this underlies the S_s S_i accidental term and the optimization over µ_both.
  • ad hoc to paper Accidental coincidence probability equals product of the total singles rates, A = S_s S_i, even when FHE is imperfect.
    Eqs. (3)-(4) and App. B; this is the load-bearing step for Eq. (7).
  • domain assumption SpRS noise is broadband, constant across the narrow filter passbands, and unpolarized after fiber propagation (α_pol = 1/2).
    Section II; enables D_j = (η_r α_pol R_j Δλ_j + d_j) ΔT_j.
  • ad hoc to paper The Gaussian approximation for pump, phase-matching, and filter functions (sinc ≈ exp(-0.193x^2)) is accurate enough for the FHE/purity simulations in Figs. 5-6.
    Appendix D, following refs. [57,84]; not tested against measured JSA for all pump widths.
  • domain assumption Detection time window ΔT is wide enough not to truncate the joint temporal amplitude (τ_ph/τ_p≈1.5 at 50 pm).
    Appendix A; used for time-bin experiment and noise modeling.

pith-pipeline@v1.3.0-alltime-deepseek · 26628 in / 15742 out tokens · 128818 ms · 2026-08-04T11:08:37.613662+00:00 · methodology

0 comments
Cite this review

Pith. "Pith review of Optimal filtering and generation of entangled photons for quantum applications in the presence of noise." pith.science (2026). https://pith.science/paper/CEYPBBQ3

@misc{pith2026251006536,
  author       = {Pith},
  title        = {Pith review of: Optimal filtering and generation of entangled photons for quantum applications in the presence of noise},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/CEYPBBQ3}},
  note         = {Machine review of arXiv:2510.06536}
}
Share X Bluesky LinkedIn Reddit HN
read the original abstract

Filtering is commonly used in quantum optics to reject noise photons, and also to enable interference between independent photons. However, filtering the joint spectrum of photon pairs can reduce the inherent coincidence probability or loss-independent heralding efficiency. Here, we investigate filtering for multiphoton applications based on entanglement and interference (e.g., quantum teleportation). We multiplex C-band entangled photons and C-band classical communications into the same long-distance fibers, which enables scalable low-loss quantum networking but requires filtering of spontaneous Raman scattering noise from classical light. Using tunable-bandwidth filters, low-jitter detectors, and polarization filters, we co-propagate time-bin-entangled photons at wavelengths compatible with erbium-ion quantum memories (1536.5 nm) and 10-Gbps C-band classical data over 25 km/25 km of standard fiber. Narrow filtering enables mW-level C-band power, which exceeds comparable studies by roughly an order of magnitude and could feasibly support Tbps classical rates. We evaluate how performance depends on pump and filter bandwidths, multipair emission, filter shapes, loss, phase matching, and how quantum information is measured. We find a trade-off between improving noise impact and single-mode purity and discuss mitigation methods toward optimal multiphoton applications. Importantly, these results apply to noise in free space and in quantum devices (sources, frequency converters, switches, detectors, etc.) and provide insight on filter-induced degradation of single-photon purity and rates even in noise-free environments.

Figures

Figures reproduced from arXiv: 2510.06536 by Akil Pathiranage, Andrew R. Cameron, Cristi\'an Pe\~na, Jordan M. Thomas, Maria Spiropulu, Panagiotis Spentzouris, Prem Kumar, Raju Valivarthi, Si Xie.

Figure 1
Figure 1. Figure 1: FIG. 1. (a) Conceptual diagram for polarization, frequency, and time filtering around photon pairs in the presence of background [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. (a) Measured JSI of the type-II SPDC pho [PITH_FULL_IMAGE:figures/full_fig_p005_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. CAR as a function of the spectral filter bandwidth [PITH_FULL_IMAGE:figures/full_fig_p006_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. Results for distributing 1536.5-nm time-bin entangled photons over 25-km/25-km fibers with a co-propagating 10-Gbps [PITH_FULL_IMAGE:figures/full_fig_p007_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5. (a) CAR as a function of filter bandwidth for ei [PITH_FULL_IMAGE:figures/full_fig_p009_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6. Simulation of the impact of a source’s pump pulse width ( [PITH_FULL_IMAGE:figures/full_fig_p010_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: FIG. 7. Characterization of the shape of the tunable band [PITH_FULL_IMAGE:figures/full_fig_p015_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: FIG. 8. (a) Normalized singles counts relative to the clock [PITH_FULL_IMAGE:figures/full_fig_p016_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: FIG. 9. (a) CAR versus [PITH_FULL_IMAGE:figures/full_fig_p018_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: FIG. 10. Comparison between time-bin entanglement distri [PITH_FULL_IMAGE:figures/full_fig_p020_10.png] view at source ↗

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

91 extracted references · 1 canonical work pages

  1. [1]

    H. J. Kimble, The quantum internet, Nature453, 1023 (2008)

    2008

  2. [2]

    Wehner, D

    S. Wehner, D. Elkouss, and R. Hanson, Quantum inter- net: A vision for the road ahead, Science362, eaam9288 (2018)

    2018

  3. [3]

    S.-H. Wei, B. Jing, X.-Y. Zhang, J.-Y. Liao, C.-Z. Yuan, B.-Y. Fan, C. Lyu, D.-L. Zhou, Y. Wang, G.-W. Deng, H.-Z. Song, D. Oblak, G.-C. Guo, and Q. Zhou, Towards real-world quantum networks: A review, Laser & Pho- tonics Reviews16, 2100219 (2022)

    2022

  4. [4]

    P. D. Townsend, Simultaneous quantum cryptographic key distribution and conventional data transmission over installed fibre using wavelength-division multiplexing, Electronics Letters33, 188 (1997), publisher: Institution of Engineering and Technology

    1997

  5. [5]

    Liang, K

    C. Liang, K. F. Lee, J. Chen, and P. Kumar, Distri- bution of fiber-generated polarization entangled photon- pairs over 100 km of standard fiber in oc-192 wdm envi- ronment, in2006 Optical Fiber Communication Confer- ence and the National Fiber Optic Engineers Conference (2006) pp. 1–3

    2006

  6. [6]

    N. I. Nweke, P. Toliver, R. J. Runser, S. R. McNown, J. B. Khurgin, T. E. Chapuran, M. S. Goodman, R. J. Hughes, C. G. Peterson, K. McCabe, J. E. Nordholt, K. Tyagi, P. Hiskett, and N. Dallmann, Experimental characterization of the separation be- tween wavelength-multiplexed quantum and classical communication channels, Applied Physics Letters 87, 174103 ...

    work page doi:10.1063/1.2117616/14650478/174103_1_online.pdf 2005

  7. [7]

    T. E. Chapuran, P. Toliver, N. A. Peters, J. Jackel, M. S. Goodman, R. J. Runser, S. R. McNown, N. Dallmann, R. J. Hughes, K. P. McCabe, J. E. Nordholt, C. G. Peter- son, K. T. Tyagi, L. Mercer, and H. Dardy, Optical net- working for quantum key distribution and quantum com- munications, New Journal of Physics11, 105001 (2009)

    2009

  8. [8]

    Eraerds, N

    P. Eraerds, N. Walenta, M. Legré, N. Gisin, and H. Zbinden, Quantum key distribution and 1 Gbps data encryption over a single fibre, New Journal of Physics12, 063027 (2010)

    2010

  9. [9]

    J. F. Dynes, W. W.-S. Tam, A. Plews, B. Fröhlich, A. W. Sharpe, M. Lucamarini, Z. Yuan, C. Radig, A. Straw, T. Edwards, and A. J. Shields, Ultra-high bandwidth quantum secured data transmission, Scientific Reports 6, 35149 (2016)

    2016

  10. [10]

    Mao, B.-X

    Y. Mao, B.-X. Wang, C. Zhao, G. Wang, R. Wang, H. Wang, F. Zhou, J. Nie, Q. Chen, Y. Zhao, Q. Zhang, J. Zhang, T.-Y. Chen, and J.-W. Pan, Integrating quan- tum key distribution with classical communications in backbone fiber network, Opt. Express26, 6010 (2018)

    2018

  11. [11]

    Valivarthi, P

    R. Valivarthi, P. Umesh, C. John, K. A. Owen, V. B. Verma, S. W. Nam, D. Oblak, Q. Zhou, and W. Tittel, Measurement-device-independent quantum key distribu- tion coexisting with classical communication, Quantum Science and Technology4, 045002 (2019)

    2019

  12. [12]

    J. M. Thomas, G. S. Kanter, and P. Kumar, Designing noise-robust quantum networks coexisting in the classical fiber infrastructure, Opt. Express31, 43035 (2023)

    2023

  13. [13]

    Y.-R. Fan, Y. Luo, Z.-C. Zhang, Y.-B. Li, S. Liu, D. Wang, D.-C. Zhang, G.-W. Deng, Y. Wang, H.- Z. Song, Z. Wang, L.-X. You, C.-Z. Yuan, G.-C. Guo, and Q. Zhou, Energy-time entanglement coexisting with fiber-optical communication in the telecomcband, Phys. Rev. A108, L020601 (2023)

    2023

  14. [14]

    J. M. Thomas, G. S. Kanter, S. Xie, J. Chung, R. Valivarthi, C. Peña, R. Kettimuthu, P. Spentzouris, M. Spiropulu, and P. Kumar, Optimization of classical light wavelengths coexisting with c-band quantum net- works for minimal noise impact, inOptical Fiber Com- munication Conference (OFC) 2023(Optica Publishing Group, 2023) p. Tu3I.3

    2023

  15. [15]

    I. A. Burenkov, A. Semionov, Hala, T. Gerrits, A. Rah- mouni, D. Anand, Y.-S. Li-Baboud, O. Slattery, A. Bat- tou, and S. V. Polyakov, Synchronization and coexistence in quantum networks, Opt. Express31, 11431 (2023)

    2023

  16. [16]

    R. Wang, R. Yang, M. J. Clark, R. D. Oliveira, S. Bahrani, M. Peranić, M. Lončarić, M. Stipčević, J. Rarity, S. K. Joshi, S. K. Joshi, R. Nejabati, and D. Simeonidou, Field trial of a dynamically switched quantum network supporting co-existence of entangle- ment, prepare-and-measure qkd and classical channels, in49th European Conference on Optical Communi...

    2023

  17. [17]

    Rahmouni, P

    A. Rahmouni, P. S. Kuo, Y. S. Li-Baboud, I. A. Bu- renkov, Y. Shi, M. V. Jabir, N. Lal, D. Reddy, M. Mer- zouki, L. Ma, A. Battou, S. V. Polyakov, O. Slattery, and T. Gerrits, 100-km entanglement distribution with coex- isting quantum and classical signals in a single fiber, J. Opt. Commun. Netw.16, 781 (2024). 13

    2024

  18. [18]

    X. Jing, C. Qian, X. Zheng, H. Nian, C. Wang, J. Tang, X. Gu, Y. Kong, T. Chen, Y. Liu, C. Sheng, D. Jiang, B.Niu,andL.Lu,Coexistenceofmultiuserentanglement distribution and classical light in optical fiber network with a semiconductor chip, Chip , 100083 (2024)

    2024

  19. [19]

    Zhong, X.-H

    Z.-Q. Zhong, X.-H. Zhan, J.-L. Chen, S. Wang, Z.-Q. Yin, J.-Q. Geng, D.-Y. He, W. Chen, G.-C. Guo, and Z.-F. Han, Hyperentanglement quantum communication over a 50 km noisy fiber channel, Optica11, 1056 (2024)

    2024

  20. [20]

    J. M. Thomas, F. I. Yeh, J. H. Chen, J. J. Mambretti, S. J. Kohlert, G. S. Kanter, and P. Kumar, Quantum teleportation coexisting with classical communications in optical fiber, Optica11, 1700 (2024)

    2024

  21. [21]

    T. Dou, R. Liu, S. Liao, J. Tang, J. Tong, R. Ma, Y. Wan, R. Wang, J. Wu, X. Zhang, Z. Pan, Y. Li, C. Zhang, and S. Tang, Coexistence of 11 tbps (110×100 gbps) clas- sical optical communication and quantum key distribu- tion based on single-mode fiber, Opt. Express32, 28356 (2024)

    2024

  22. [22]

    J. M. Thomas, G. S. Kanter, and P. Kumar, Multiphoton interference and quantum teleportation coexisting with classical communications in optical fiber, inQuantum Communications and Quantum Imaging XXIII,Proceed- ings of SPIE, Vol. 13391 (SPIE, 2024) pp. 13391–28

    2024

  23. [23]

    A. Sanz, A. Atutxa, D. Franco, J. Astorga, and E. Jacob, Adapting communication networks to the quantum safe era: lessons learned in the coexistence of polarization- entangled qkd and classical channels, in2025 Interna- tional Conference on Quantum Communications, Net- working, and Computing (QCNC)(IEEE, 2025) pp. 110– 116

    2025

  24. [24]

    G. Gül, G. S. Kanter, S. G. Tan, M. B. On, R. Proietti, S. J. B. Yoo, and P. Kumar, Noise impact of classical headers on the quantum payload in quantum wrapper networking, Optica Quantum3, 303 (2025)

    2025

  25. [25]

    M. Sena, M. Flament, S. Andrewski, I. Caltzidis, N. Bigagli, T. Rieser, G. B. Portmann, R. Sekelsky, R.-P. Braun, A. N. Craddock,et al., Robust high- fidelity quantum entanglement distribution over large- scale metropolitan fiber networks with co-propagating classicalsignals,arXivpreprintarXiv:2504.08927 (2025)

    arXiv 2025

  26. [26]

    Zhang, R

    Y. Zhang, R. Broberg, A. Zhu, G. Li, L. Ge, J. M. Smith, and L. Feng, Classical-decisive quantum internet by in- tegrated photonics, Science389, 940 (2025)

    2025

  27. [27]

    J. M. Thomas, G. M. Talcott, G. S. Kanter, and P. Ku- mar, Comparing teleportation to direct transmission in high-noise fibers carrying classical communications, in CLEO: Fundamental Science(Optica Publishing Group,

  28. [28]

    C.-Z. Peng, T. Yang, X.-H. Bao, J. Zhang, X.-M. Jin, F.-Y. Feng, B. Yang, J. Yang, J. Yin, Q. Zhang, N. Li, B.-L. Tian, and J.-W. Pan, Experimental free-space dis- tribution of entangled photon pairs over 13 km: To- wards satellite-based global quantum communication, Phys. Rev. Lett.94, 150501 (2005)

    2005

  29. [29]

    Ursin, F

    R. Ursin, F. Tiefenbacher, T. Schmitt-Manderbach, H. Weier, T. Scheidl, M. Lindenthal, B. Blauensteiner, T. Jennewein, J. Perdigues, P. Trojek, B. Ömer, M. Fürst, M. Meyenburg, J. Rarity, Z. Sodnik, C. Barbi- eri, H. Weinfurter, and A. Zeilinger, Entanglement-based quantum communication over 144 km, Nat. Phys.3, 481 (2007)

    2007

  30. [30]

    H. Ko, K. Kim, J. Choe, B. Choi, J. Kim, Y. Baek, and C. J. Youn, Experimental filtering effect on the daylight operation of a free-space quantum key distribution, Sci. Rep.8, 15315 (2018)

    2018

  31. [31]

    Bouchard, D

    F. Bouchard, D. England, P. J. Bustard, K. L. Fen- wick, E. Karimi, K. Heshami, and B. Sussman, Achieving Ultimate Noise Tolerance in Quantum Communication, Physical Review Applied15, 024027 (2021)

    2021

  32. [32]

    F. B. Basset, M. B. Rota, G. Beccaceci, T. M. Krieger, Q. Buchinger, J. Neuwirth, H. Huet, S. Stroj, S. F. C. da Silva, G. Ronco, C. Schimpf, S. Höfling, T. Huber-Loyol, A. Rastelli, and R. Trotta, Daylight entanglement-based quantum key distribution with a blinking-free quantum dot operated at a temperature up to 20k, Quantum Science and Technology8, 025...

    2023

  33. [33]

    W.-Q. Cai, Y. Li, B. Li, J.-G. Ren, S.-K. Liao, Y. Cao, L. Zhang, M. Yang, J.-C. Wu, Y.-H. Li, W.-Y. Liu, J. Yin, C.-Z. Wang, W.-B. Luo, B. Jin, C.-L. Lv, H. Li, L. You, R. Shu, G.-S. Pan, Q. Zhang, N.-L. Liu, X.-B. Wang, J.-Y. Wang, C.-Z. Peng, and J.-W. Pan, Free- space quantum key distribution during daylight and at night, Optica11, 647 (2024)

    2024

  34. [34]

    X. Li, P. L. Voss, J. E. Sharping, and P. Kumar, Optical- fiber source of polarization-entangled photons in the 1550 nm telecom band, Phys. Rev. Lett.94, 053601 (2005)

    2005

  35. [35]

    Q. Lin, F. Yaman, and G. P. Agrawal, Photon-pair gen- eration in optical fibers through four-wave mixing: Role of raman scattering and pump polarization, Phys. Rev. A75, 023803 (2007)

    2007

  36. [36]

    P. S. Kuo, J. S. Pelc, C. Langrock, and M. M. Fejer, Using temperature to reduce noise in quantum frequency conversion, Opt. Lett.43, 2034 (2018)

    2034

  37. [37]

    M. L. H. Korsgaard, J. G. Koefoed, and K. Rottwitt, Ra- man effects in quantum frequency conversion using bragg scattering, Phys. Rev. A110, 033508 (2024)

    2024

  38. [38]

    M. A. Hall, J. B. Altepeter, and P. Kumar, Ultrafast switching of photonic entanglement, Phys. Rev. Lett. 106, 053901 (2011)

    2011

  39. [39]

    A. R. Cameron, K. L. Fenwick, S. W. L. Cheng, S. Schwarz, B. MacLellan, P. J. Bustard, D. England, B. Sussman, and K. J. Resch, Ultrafast measurement of energy-time entanglement with an optical kerr shutter, Phys. Rev. A108, L041503 (2023)

    2023

  40. [40]

    Kupchak, J

    C. Kupchak, J. Erskine, D. England, and B. Sussman, Terahertz-bandwidth switching of heralded single pho- tons, Opt. Lett.44, 1427 (2019)

    2019

  41. [41]

    Shahverdi, Y

    A. Shahverdi, Y. M. Sua, L. Tumeh, and Y.-P. Huang, Quantum parametric mode sorting: Beating the time- frequency filtering, Scientific Reports7, 6495 (2017)

    2017

  42. [42]

    S. Gao, O. Lazo-Arjona, B. Brecht, K. T. Kaczmarek, S.E.Thomas, J.Nunn, P.M.Ledingham, D.J.Saunders, and I. A. Walmsley, Optimal coherent filtering for sin- gle noisy photons, Physical Review Letters123, 213604 14 (2019)

    2019

  43. [43]

    M. G. Raymer and K. Banaszek, Time-frequency opti- cal filtering: efficiency vs. temporal-mode discrimination in incoherent and coherent implementations, Optics Ex- press28, 32819 (2020)

    2020

  44. [44]

    C. K. Hong, Z. Y. Ou, and L. Mandel, Measurement of subpicosecond time intervals between two photons by in- terference, Phys. Rev. Lett.59, 2044 (1987)

    2044

  45. [45]

    J. G. Rarity, Interference of single photons from separate sources, Annals of the New York Academy of Sciences755, 624 (1995), https://nyaspubs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1749- 6632.1995.tb39002.x

    arXiv 1995

  46. [46]

    S. L. Braunstein and A. Mann, Measurement of the bell operator and quantum teleportation, Phys. Rev. A51, R1727 (1995)

    1995

  47. [47]

    event-ready-detectors

    M. Żukowski, A. Zeilinger, M. A. Horne, and A. K. Ekert, “event-ready-detectors” bellexperimentviaentanglement swapping, Phys. Rev. Lett.71, 4287 (1993)

    1993

  48. [48]

    Zeilinger, M

    A. Zeilinger, M. A. Horne, H. Weinfurter, and M. Żukowski, Three-particle entanglements from two en- tangled pairs, Phys. Rev. Lett.78, 3031 (1997)

    1997

  49. [49]

    Knill, R

    E. Knill, R. Laflamme, and G. J. Milburn, A scheme for efficient quantum computation with linear optics, Nature 409, 46 (2001)

    2001

  50. [50]

    PsiQuantum Team, A manufacturable platform for pho- tonic quantum computing, Nature641, 876 (2025)

    2025

  51. [51]

    Pan, Z.-B

    J.-W. Pan, Z.-B. Chen, C.-Y. Lu, H. Weinfurter, A. Zeilinger, and M. Żukowski, Multiphoton entangle- ment and interferometry, Rev. Mod. Phys.84, 777 (2012)

    2012

  52. [52]

    Bouchard, A

    F. Bouchard, A. Sit, Y. Zhang, R. Fickler, F. M. Miatto, Y. Yao, F. Sciarrino, and E. Karimi, Two-photon inter- ference: the hong-ou-mandel effect, Reports on Progress in Physics84, 012402 (2021)

    2021

  53. [53]

    W. P. Grice and I. A. Walmsley, Spectral information and distinguishability in type-ii down-conversion with a broadband pump, Phys. Rev. A56, 1627 (1997)

    1997

  54. [54]

    P. J. Mosley, J. S. Lundeen, B. J. Smith, P. Wasylczyk, A. B. U’Ren, C. Silberhorn, and I. A. Walmsley, Heralded generation of ultrafast single photons in pure quantum states, Phys. Rev. Lett.100, 133601 (2008)

    2008

  55. [55]

    L. Yang, X. Ma, X. Guo, L. Cui, and X. Li, Characteri- zation of a fiber-based source of heralded single photons, Phys. Rev. A83, 053843 (2011)

    2011

  56. [56]

    J. Jin, M. Grimau Puigibert, L. Giner, J. A. Slater, M. R. E. Lamont, V. B. Verma, M. D. Shaw, F. Mar- sili, S. W. Nam, D. Oblak, and W. Tittel, Entangle- ment swapping with quantum-memory-compatible pho- tons, Phys. Rev. A92, 012329 (2015)

    2015

  57. [57]

    Meyer-Scott, N

    E. Meyer-Scott, N. Montaut, J. Tiedau, L. Sansoni, H. Herrmann, T. J. Bartley, and C. Silberhorn, Limits on the heralding efficiencies and spectral purities of spec- trally filtered single photons from photon-pair sources, Phys. Rev. A95, 061803 (2017)

    2017

  58. [58]

    L. Cui, J. Su, J. Li, Y. Liu, X. Li, and Z. Y. Ou, Quan- tum state engineering by nonlinear quantum interference, Phys. Rev. A102, 033718 (2020)

    2020

  59. [59]

    Zhan et al., Measurement-device-independent quantum key distribution with practical spontaneous parametric down-conversion sources, Phys

    X.-H. Zhan et al., Measurement-device-independent quantum key distribution with practical spontaneous parametric down-conversion sources, Phys. Rev. Appl. 20, 034069 (2023)

    2023

  60. [60]

    Mueller, S

    A. Mueller, S. I. Davis, B. Korzh, R. Valivarthi, A. D. Beyer, R. Youssef, N. Sinclair, C. Peña, M. D. Shaw, and M. Spiropulu, High-rate multiplexed entanglement source based on time-bin qubits for advanced quantum networks, Optica Quantum2, 64 (2024)

    2024

  61. [61]

    Grice, A

    W. Grice, A. B. U’Ren, and I. A. Walmsley, Eliminat- ing frequency and space-time correlations in multiphoton states, Phys. Rev. A64, 063815 (2001)

    2001

  62. [62]

    Garay-Palmett, H

    K. Garay-Palmett, H. McGuinness, O. Cohen, J. Lun- deen, R. Rangel-Rojo, A. U’ren, M. Raymer, C. McKin- strie, S. Radic, and I. Walmsley, Photon pair-state prepa- ration with tailored spectral properties by spontaneous four-wave mixing in photonic-crystal fiber, Optics ex- press15, 14870 (2007)

    2007

  63. [63]

    Halder, J

    M. Halder, J. Fulconis, B. Cemlyn, A. Clark, C. Xiong, W. J. Wadsworth, and J. G. Rarity, Nonclassical 2- photon interference with separate intrinsically narrow- band fibre sources, Optics express17, 4670 (2009)

    2009

  64. [64]

    Jeronimo-Moreno, S

    Y. Jeronimo-Moreno, S. Rodriguez-Benavides, and A. B. U’Ren, Theory of cavity-enhanced spontaneous paramet- ric downconversion, Laser Physics20, 1221 (2010)

    2010

  65. [65]

    Eckstein, A

    A. Eckstein, A. Christ, P. J. Mosley, and C. Silberhorn, Highly efficient single-pass source of pulsed single-mode twin beams of light, Phys. Rev. Lett.106, 013603 (2011)

    2011

  66. [66]

    B.Fang, O.Cohen, J.B.Moreno,andV.O.Lorenz,State engineering of photon pairs produced through dual-pump spontaneous four-wave mixing, Optics express21, 2707 (2013)

    2013

  67. [67]

    Rieländer, A

    D. Rieländer, A. Lenhard, M. Mazzera, and H. de Ried- matten, Cavity enhanced telecom heralded single pho- tons for spin-wave solid state quantum memories, New Journal of Physics18, 123013 (2016)

    2016

  68. [68]

    Paesani, M

    S. Paesani, M. Borghi, S. Signorini, A. Maïnos, L. Pavesi, and A. Laing, Near-ideal spontaneous photon sources in silicon quantum photonics, Nature Communications11, 10.1038/s41467-020-16187-8 (2020)

    doi:10.1038/s41467-020-16187-8 2020

  69. [69]

    Y. Liu, C. Wu, X. Gu, Y. Kong, X. Yu, R. Ge, X. Cai, X. Qiang, J. Wu, X. Yang, and P. Xu, High-spectral- purity photon generation from a dual-interferometer- coupled silicon microring, Opt. Lett.45, 73 (2020)

    2020

  70. [70]

    C. Xin, J. Mishra, C. Chen, D. Zhu, A. Shams-Ansari, C. Langrock, N. Sinclair, F. N. Wong, M. Fejer, and M. Lončar, Spectrally separable photon-pair generation in dispersion engineered thin-film lithium niobate, Optics Letters47, 2830 (2022)

    2022

  71. [71]

    Takesue, H

    H. Takesue, H. Fukuda, T. Tsuchizawa, T. Watanabe, K. Yamada, and S. Itabashi, Implementation of quantum state tomography for time-bin entangled photon pairs, Optics Express16, 5721 (2008)

    2008

  72. [72]

    Lauritzen, J

    B. Lauritzen, J. c. v. Minář, H. de Riedmatten, M. Afzelius, N. Sangouard, C. Simon, and N. Gisin, Telecommunication-wavelength solid-state memory at the single photon level, Phys. Rev. Lett.104, 080502 (2010). 15

    2010

  73. [73]

    Y.-Y. An, Q. He, W. Xue, M.-H. Jiang, C. Yang, Y.- Q. Lu, S. Zhu, and X.-S. Ma, Quantum teleportation from telecom photons to erbium-ion ensembles, Phys. Rev. Lett.135, 010804 (2025)

    2025

  74. [74]

    Stolen, Issues in raman gain measurements, inTech- nical Digest: Symposium on Optical Fiber Measurements (IEEE, 2001) p

    R. Stolen, Issues in raman gain measurements, inTech- nical Digest: Symposium on Optical Fiber Measurements (IEEE, 2001) p. 139–140

    2001

  75. [75]

    J. C. Chapman, J. M. Lukens, M. Alshowkan, N. Rao, B. T. Kirby, and N. A. Peters, Coexistent quantum chan- nel characterization using spectrally resolved bayesian quantum process tomography, Phys. Rev. Appl.19, 044026 (2023)

    2023

  76. [76]

    Shih and C

    Y. Shih and C. Alley, New type of einstein-podolsky- rosen-bohm experiment using pairs of light quanta pro- duced by optical parametric down conversion, Physical Review Letters61, 2921 (1988)

    1988

  77. [77]

    Takesue and K

    H. Takesue and K. Shimizu, Effects of multiple pairs on visibility measurements of entangled photons generated by spontaneous parametric processes, Optics Communi- cations283, 276 (2010)

    2010

  78. [78]

    Takeoka, R.-B

    M. Takeoka, R.-B. Jin, and M. Sasaki, Full analysis of multi-photon pair effects in spontaneous parametric down conversion based photonic quantum information processing, New Journal of Physics17, 043030 (2015)

    2015

  79. [79]

    Takesue, Long-distance distribution of time-bin en- tanglement generated in a cooled fiber, Optics Express 14, 3453 (2006)

    H. Takesue, Long-distance distribution of time-bin en- tanglement generated in a cooled fiber, Optics Express 14, 3453 (2006)

    2006

  80. [80]

    Brendel, N

    J. Brendel, N. Gisin, W. Tittel, and H. Zbinden, Pulsed energy-time entangled twin-photon source for quantum communication,PhysicalReviewLetters82,2594(1999)

    1999

Showing first 80 references.