1.
Nafria, Vijay; Djordjevic, Ivan B.
Amplified entanglement-assisted communication systems operated in a desert environment and strong atmospheric turbulence regime Journal Article
In: Optics Express, vol. 32, no. 26, pp. 47561–47573, 2024, ISSN: 1094-4087, (Publisher: Optica Publishing Group).
Abstract | Links | BibTeX | Tags: Homodyne detection, Laser communications, Optical properties, Optical transceivers, Rayleigh scattering, Signal processing
@article{nafria_amplified_2024,
title = {Amplified entanglement-assisted communication systems operated in a desert environment and strong atmospheric turbulence regime},
author = {Vijay Nafria and Ivan B. Djordjevic},
url = {https://opg.optica.org/oe/abstract.cfm?uri=oe-32-26-47561},
doi = {10.1364/OE.543021},
issn = {1094-4087},
year = {2024},
date = {2024-12-01},
urldate = {2025-10-08},
journal = {Optics Express},
volume = {32},
number = {26},
pages = {47561–47573},
publisher = {Optica Publishing Group},
abstract = {In this paper, we are presenting results that go against the common belief that entanglement is destroyed by the amplification using an EDFA. Here we demonstrate the quantum advantage of entanglement-assisted communication at 10Gb/s, employing LDPC-coded BPSK, over classical laser communication even after the amplification of signal photons is performed by the EDFA in order to improve the reliability of entanglement-assisted (EA) communication operating in turbulent 1.5 km terrestrial FSO channels. To make the EA system more robust against various atmospheric effects such as scattering, absorption, and turbulence effects we perform the optical phase-conjugation on idler photons rather than turbulence-affected signal photons and use adaptive optics to make additional improvements in terms of the bit-error rate.},
note = {Publisher: Optica Publishing Group},
keywords = {Homodyne detection, Laser communications, Optical properties, Optical transceivers, Rayleigh scattering, Signal processing},
pubstate = {published},
tppubtype = {article}
}
In this paper, we are presenting results that go against the common belief that entanglement is destroyed by the amplification using an EDFA. Here we demonstrate the quantum advantage of entanglement-assisted communication at 10Gb/s, employing LDPC-coded BPSK, over classical laser communication even after the amplification of signal photons is performed by the EDFA in order to improve the reliability of entanglement-assisted (EA) communication operating in turbulent 1.5 km terrestrial FSO channels. To make the EA system more robust against various atmospheric effects such as scattering, absorption, and turbulence effects we perform the optical phase-conjugation on idler photons rather than turbulence-affected signal photons and use adaptive optics to make additional improvements in terms of the bit-error rate.
2.
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.
3.
Chen, Lin; Wang, Xinyu; Jin, Wei; Huang, Xiaoyu; Yang, Gang; Jiang, Mingyang; Tang, Jianming
In: IET Optoelectronics, vol. 18, no. 1-2, pp. 41–47, 2024, ISSN: 1751-8776, (_eprint: https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/ote2.12115).
Abstract | Links | BibTeX | Tags: optical fibre communication, Optical transceivers
@article{chen_point–point_2024,
title = {Point-to-point intensity modulation and direct detection flexible transceivers incorporating cascaded inverse fast fourier transform/fast fourier transform-based multi-channel aggregation/de-aggregation techniques},
author = {Lin Chen and Xinyu Wang and Wei Jin and Xiaoyu Huang and Gang Yang and Mingyang Jiang and Jianming Tang},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1049/ote2.12115},
doi = {10.1049/ote2.12115},
issn = {1751-8776},
year = {2024},
date = {2024-01-01},
urldate = {2025-10-08},
journal = {IET Optoelectronics},
volume = {18},
number = {1-2},
pages = {41–47},
abstract = {Point-to-point (P2P) flexible transceivers are the key technical enabler to cost-effectively offer fast, dynamic, and ‘just-the-right-size’ ultra-dense P2P connectivity for various applications including remote equipment control and distributed fibre networks. However, existing flexible transceivers originally designed for hub-and-spoke traffic patterns are sub-optimal. To effectively address such technical issue, a P2P flexible transceiver incorporating a cascaded inverse fast fourier transform/fast fourier transform-based multi-channel aggregation/de-aggregation technique and analogue in-phase and quadrature (IQ) mixers is proposed and numerically evaluated in a 56Gbps@20 km intensity modulation and direct detection transmission system. The proposed P2P flexible transceivers not only support adaptive and flexible variations in both channel count and channel line rate but also offer additional physical layer network security.},
note = {_eprint: https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/ote2.12115},
keywords = {optical fibre communication, Optical transceivers},
pubstate = {published},
tppubtype = {article}
}
Point-to-point (P2P) flexible transceivers are the key technical enabler to cost-effectively offer fast, dynamic, and ‘just-the-right-size’ ultra-dense P2P connectivity for various applications including remote equipment control and distributed fibre networks. However, existing flexible transceivers originally designed for hub-and-spoke traffic patterns are sub-optimal. To effectively address such technical issue, a P2P flexible transceiver incorporating a cascaded inverse fast fourier transform/fast fourier transform-based multi-channel aggregation/de-aggregation technique and analogue in-phase and quadrature (IQ) mixers is proposed and numerically evaluated in a 56Gbps@20 km intensity modulation and direct detection transmission system. The proposed P2P flexible transceivers not only support adaptive and flexible variations in both channel count and channel line rate but also offer additional physical layer network security.