1.
He, Jiaxiang; Vallejo, Luis; Giddings, Roger Philip; Jin, Wei; Faruk, Md Saifuddin; Yi, Xingwen; Tang, Jianming
Experimental Demonstrations of Chaotic Digital Filter-Based Physical Layer Security in Converged Fibre-mmWave Access Networks Journal Article
In: Journal of Lightwave Technology, vol. 43, no. 18, pp. 8839–8848, 2025, (Publisher: IEEE).
Abstract | Links | BibTeX | Tags: Bit error rate, Frequency division multiplexing, Optical signals, Phase noise, Quantum key distribution, Single mode fibers
@article{he_experimental_2025,
title = {Experimental Demonstrations of Chaotic Digital Filter-Based Physical Layer Security in Converged Fibre-mmWave Access Networks},
author = {Jiaxiang He and Luis Vallejo and Roger Philip Giddings and Wei Jin and Md Saifuddin Faruk and Xingwen Yi and Jianming Tang},
url = {https://opg.optica.org/jlt/abstract.cfm?uri=jlt-43-18-8839},
year = {2025},
date = {2025-09-01},
urldate = {2025-10-08},
journal = {Journal of Lightwave Technology},
volume = {43},
number = {18},
pages = {8839–8848},
publisher = {IEEE},
abstract = {Secure data transmission is experimentally demonstrated in a 1.67 Gb/s seamlessly converged fibre–millimeter wave (mmWave) network using the authors’ newly proposed chaotic digital filter (CDF)-based physical layer security (PLS) technique. The CDF-based encryption/decryption operates by introducing noise-like, key-dependent phase variations to conventional filter impulse responses. Validation is performed in a seamlessly converged network comprising a 25 km standard single-mode fibre (SSMF) link and a 5 m 36 GHz mmWave wireless link, utilizing cost-effective photonic-based mmWave generation and envelope detector-based reception. Experimental results show that the demonstrated PLS technique allows the encrypted signals to continuously flow between the fibre and radio frequency (RF) domains. The PLS technique also supports simultaneous optical and radio frequency access with almost identical BER transmission performances, and power penalties of <1 dB. To gain an in-depth understanding of the measured results, the CDFs’ characteristics, including their chaotic nature, sensitivity to security keys and optimum CDF design parameters, are explored both theoretically and experimentally in detail. The optimum security key properties and CDF's filter lengths are identified, which are independent of the transmission media and major characteristics of the encrypted signals. The CDF-based PLS technique offers salient advantages of ‘security-by-design’, ‘openness-by-design’, ‘dynamic security at the traffic level’, and ‘universal network compatibility’.},
note = {Publisher: IEEE},
keywords = {Bit error rate, Frequency division multiplexing, Optical signals, Phase noise, Quantum key distribution, Single mode fibers},
pubstate = {published},
tppubtype = {article}
}
Secure data transmission is experimentally demonstrated in a 1.67 Gb/s seamlessly converged fibre–millimeter wave (mmWave) network using the authors’ newly proposed chaotic digital filter (CDF)-based physical layer security (PLS) technique. The CDF-based encryption/decryption operates by introducing noise-like, key-dependent phase variations to conventional filter impulse responses. Validation is performed in a seamlessly converged network comprising a 25 km standard single-mode fibre (SSMF) link and a 5 m 36 GHz mmWave wireless link, utilizing cost-effective photonic-based mmWave generation and envelope detector-based reception. Experimental results show that the demonstrated PLS technique allows the encrypted signals to continuously flow between the fibre and radio frequency (RF) domains. The PLS technique also supports simultaneous optical and radio frequency access with almost identical BER transmission performances, and power penalties of <1 dB. To gain an in-depth understanding of the measured results, the CDFs’ characteristics, including their chaotic nature, sensitivity to security keys and optimum CDF design parameters, are explored both theoretically and experimentally in detail. The optimum security key properties and CDF's filter lengths are identified, which are independent of the transmission media and major characteristics of the encrypted signals. The CDF-based PLS technique offers salient advantages of ‘security-by-design’, ‘openness-by-design’, ‘dynamic security at the traffic level’, and ‘universal network compatibility’.
2.
Hu, Shaohua; Wang, Shen; Tang, Jianming; Zhang, Jing; Xu, Zhaopeng; Jin, Wei; Liu, Lulu; Zhou, Jiahao; Yi, Xingwen; Xu, Bo; Qiu, Kun
In: Optics Express, vol. 33, no. 15, pp. 31129–31138, 2025, ISSN: 1094-4087, (Publisher: Optica Publishing Group).
Abstract | Links | BibTeX | Tags: Modulation, Numerical simulation, Optical systems, Signal processing, Single mode fibers, Variable optical attenuators
@article{hu_decoupled_2025,
title = {Decoupled digital filtering-enabled simplification and fast convergence of IM/DD system linearization algorithms for strong band-limited power fading channels},
author = {Shaohua Hu and Shen Wang and Jianming Tang and Jing Zhang and Zhaopeng Xu and Wei Jin and Lulu Liu and Jiahao Zhou and Xingwen Yi and Bo Xu and Kun Qiu},
url = {https://opg.optica.org/oe/abstract.cfm?uri=oe-33-15-31129},
doi = {10.1364/OE.565790},
issn = {1094-4087},
year = {2025},
date = {2025-07-01},
urldate = {2025-10-08},
journal = {Optics Express},
volume = {33},
number = {15},
pages = {31129–31138},
publisher = {Optica Publishing Group},
abstract = {Chromatic dispersion limits practically achievable transmission distances of high data-rate intensity modulation and direct detection (IM/DD) optical transmission systems at C-band. Previously reported IM/DD system linearization algorithms can improve their transmission performances, which are, however, sensitive to the band limitation effect. In this paper, for linearizing IM/DD fiber channels with severe power fading and band-limitation, we propose and evaluate numerically and experimentally a decoupled system linearization scheme called equalization-cascaded multi-constraint iterative algorithm (EC-MCIA) using decoupled, channel partial-aware adaptive digital filters and a multiple constraint iteration algorithm. Compared with the previously reported hybrid MCIA with an embedded filter pair, the EC-MCIA can reduce the complexity and improve the linearization performance. In simulations, we observe two orders of magnitude bit-error-rate (BER) reductions for 100-Gb/s@100-km pulse amplitude modulation (PAM4) transmissions. We also experimentally demonstrate C-band 224 Gbit/s PAM4 transmissions over 25-km standard single mode fibers (SSMF). Experimental results show that the EC-MCIA achieves BERs lower than the 20% forward error correction (FEC) limit and outperforms the hybrid MCIA by nearly an order of magnitude. The required number of taps for the decoupled linear filter is only 15.},
note = {Publisher: Optica Publishing Group},
keywords = {Modulation, Numerical simulation, Optical systems, Signal processing, Single mode fibers, Variable optical attenuators},
pubstate = {published},
tppubtype = {article}
}
Chromatic dispersion limits practically achievable transmission distances of high data-rate intensity modulation and direct detection (IM/DD) optical transmission systems at C-band. Previously reported IM/DD system linearization algorithms can improve their transmission performances, which are, however, sensitive to the band limitation effect. In this paper, for linearizing IM/DD fiber channels with severe power fading and band-limitation, we propose and evaluate numerically and experimentally a decoupled system linearization scheme called equalization-cascaded multi-constraint iterative algorithm (EC-MCIA) using decoupled, channel partial-aware adaptive digital filters and a multiple constraint iteration algorithm. Compared with the previously reported hybrid MCIA with an embedded filter pair, the EC-MCIA can reduce the complexity and improve the linearization performance. In simulations, we observe two orders of magnitude bit-error-rate (BER) reductions for 100-Gb/s@100-km pulse amplitude modulation (PAM4) transmissions. We also experimentally demonstrate C-band 224 Gbit/s PAM4 transmissions over 25-km standard single mode fibers (SSMF). Experimental results show that the EC-MCIA achieves BERs lower than the 20% forward error correction (FEC) limit and outperforms the hybrid MCIA by nearly an order of magnitude. The required number of taps for the decoupled linear filter is only 15.
3.
Hu, Shaohua; Wang, Shen; Tang, Jianming; Zhang, Jing; Xu, Zhaopeng; Jin, Wei; Liu, Lulu; Zhou, Jiahao; Yi, Xingwen; Xu, Bo; Qiu, Kun
In: Optics Express, vol. 33, no. 15, pp. 31129–31138, 2025, ISSN: 1094-4087, (Publisher: Optica Publishing Group).
Abstract | Links | BibTeX | Tags: Modulation, Numerical simulation, Optical systems, Signal processing, Single mode fibers, Variable optical attenuators
@article{hu_decoupled_2025-1,
title = {Decoupled digital filtering-enabled simplification and fast convergence of IM/DD system linearization algorithms for strong band-limited power fading channels},
author = {Shaohua Hu and Shen Wang and Jianming Tang and Jing Zhang and Zhaopeng Xu and Wei Jin and Lulu Liu and Jiahao Zhou and Xingwen Yi and Bo Xu and Kun Qiu},
url = {https://opg.optica.org/oe/abstract.cfm?uri=oe-33-15-31129},
doi = {10.1364/OE.565790},
issn = {1094-4087},
year = {2025},
date = {2025-07-01},
urldate = {2025-10-08},
journal = {Optics Express},
volume = {33},
number = {15},
pages = {31129–31138},
publisher = {Optica Publishing Group},
abstract = {Chromatic dispersion limits practically achievable transmission distances of high data-rate intensity modulation and direct detection (IM/DD) optical transmission systems at C-band. Previously reported IM/DD system linearization algorithms can improve their transmission performances, which are, however, sensitive to the band limitation effect. In this paper, for linearizing IM/DD fiber channels with severe power fading and band-limitation, we propose and evaluate numerically and experimentally a decoupled system linearization scheme called equalization-cascaded multi-constraint iterative algorithm (EC-MCIA) using decoupled, channel partial-aware adaptive digital filters and a multiple constraint iteration algorithm. Compared with the previously reported hybrid MCIA with an embedded filter pair, the EC-MCIA can reduce the complexity and improve the linearization performance. In simulations, we observe two orders of magnitude bit-error-rate (BER) reductions for 100-Gb/s@100-km pulse amplitude modulation (PAM4) transmissions. We also experimentally demonstrate C-band 224 Gbit/s PAM4 transmissions over 25-km standard single mode fibers (SSMF). Experimental results show that the EC-MCIA achieves BERs lower than the 20% forward error correction (FEC) limit and outperforms the hybrid MCIA by nearly an order of magnitude. The required number of taps for the decoupled linear filter is only 15.},
note = {Publisher: Optica Publishing Group},
keywords = {Modulation, Numerical simulation, Optical systems, Signal processing, Single mode fibers, Variable optical attenuators},
pubstate = {published},
tppubtype = {article}
}
Chromatic dispersion limits practically achievable transmission distances of high data-rate intensity modulation and direct detection (IM/DD) optical transmission systems at C-band. Previously reported IM/DD system linearization algorithms can improve their transmission performances, which are, however, sensitive to the band limitation effect. In this paper, for linearizing IM/DD fiber channels with severe power fading and band-limitation, we propose and evaluate numerically and experimentally a decoupled system linearization scheme called equalization-cascaded multi-constraint iterative algorithm (EC-MCIA) using decoupled, channel partial-aware adaptive digital filters and a multiple constraint iteration algorithm. Compared with the previously reported hybrid MCIA with an embedded filter pair, the EC-MCIA can reduce the complexity and improve the linearization performance. In simulations, we observe two orders of magnitude bit-error-rate (BER) reductions for 100-Gb/s@100-km pulse amplitude modulation (PAM4) transmissions. We also experimentally demonstrate C-band 224 Gbit/s PAM4 transmissions over 25-km standard single mode fibers (SSMF). Experimental results show that the EC-MCIA achieves BERs lower than the 20% forward error correction (FEC) limit and outperforms the hybrid MCIA by nearly an order of magnitude. The required number of taps for the decoupled linear filter is only 15.