1.
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.
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_2025-1,
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.
3.
Nafria, Vijay; Djordjevic, Ivan B.
In: Optics Express, vol. 32, no. 27, pp. 47908–47919, 2024, ISSN: 1094-4087, (Publisher: Optica Publishing Group).
Abstract | Links | BibTeX | Tags: Coupling efficiency, Laser communications, Optical systems, Optical transceivers, Phase conjugation, Signal transmission
@article{nafria_entanglement_2024,
title = {Entanglement assisted free-space optical communication with two-pump-based entanglement generation outperforming classical laser communication in strong turbulence regime at 10 Gb/s},
author = {Vijay Nafria and Ivan B. Djordjevic},
url = {https://opg.optica.org/oe/abstract.cfm?uri=oe-32-27-47908},
doi = {10.1364/OE.544674},
issn = {1094-4087},
year = {2024},
date = {2024-12-01},
urldate = {2025-10-08},
journal = {Optics Express},
volume = {32},
number = {27},
pages = {47908–47919},
publisher = {Optica Publishing Group},
abstract = {A high-speed entanglement assisted communication that operates at 10 Gb/s is proposed, which performs a highly efficient, PPLN-waveguide-based, entanglement generation by making the simultaneous use of S- and L-band pumps. The two-pump-based entanglement generation source satisfies the quasi-phase-matching-condition over the entire C-band. To improve the system reliability, our system performs the phase-conjugation on idler photons in contrast to conventional ways of performing the phase-conjugation on signal photons. To study the performance of the proposed entanglement-assisted system we have developed the 1.5 km long outdoor free-space optical (FSO) link at the University of Arizona campus. Experimental results indicate that the proposed entanglement-assisted system significantly outperforms the classical counterpart at 10 Gb/s, operated in strong turbulence regime. We also demonstrate that the traditional entanglement-assisted system performing the optical phase conjugation on signal photons at the receiver side is not operational at all in strong turbulence regime given that it is extremely difficult to perform the phase-conjugation on weak signal photons when the number of received photons is low. To improve the system performance the adaptive optics is performed on signal photons.},
note = {Publisher: Optica Publishing Group},
keywords = {Coupling efficiency, Laser communications, Optical systems, Optical transceivers, Phase conjugation, Signal transmission},
pubstate = {published},
tppubtype = {article}
}
A high-speed entanglement assisted communication that operates at 10 Gb/s is proposed, which performs a highly efficient, PPLN-waveguide-based, entanglement generation by making the simultaneous use of S- and L-band pumps. The two-pump-based entanglement generation source satisfies the quasi-phase-matching-condition over the entire C-band. To improve the system reliability, our system performs the phase-conjugation on idler photons in contrast to conventional ways of performing the phase-conjugation on signal photons. To study the performance of the proposed entanglement-assisted system we have developed the 1.5 km long outdoor free-space optical (FSO) link at the University of Arizona campus. Experimental results indicate that the proposed entanglement-assisted system significantly outperforms the classical counterpart at 10 Gb/s, operated in strong turbulence regime. We also demonstrate that the traditional entanglement-assisted system performing the optical phase conjugation on signal photons at the receiver side is not operational at all in strong turbulence regime given that it is extremely difficult to perform the phase-conjugation on weak signal photons when the number of received photons is low. To improve the system performance the adaptive optics is performed on signal photons.