| 1. |
- Redaelli, L., et al.
(författare)
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Design of broadband high-efficiency superconducting-nanowire single photon detectors
- 2016
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Ingår i: Superconductors Science and Technology. - : Institute of Physics (IOP). - 0953-2048 .- 1361-6668. ; 29:6
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Tidskriftsartikel (refereegranskat)abstract
- In this paper several designs to maximize the absorption efficiency of superconducting-nanowire single-photon detectors are investigated. Using a simple optical cavity consisting of a gold mirror and a SiO2 layer, the absorption efficiency can be boosted to over 97%: this result is confirmed experimentally by the realization of an NbTiN-based detector having an overall system detection efficiency of 85% at 1.31 mu m. Calculations show that by sandwiching the nanowire between two dielectric Bragg reflectors, unity absorption (>99.9%) could be reached at the peak wavelength for optimized structures. To achieve broadband high efficiency, a different approach is considered: a waveguide-coupled detector. The calculations performed in this work show that, by correctly dimensioning the waveguide and the nanowire, polarization-insensitive detectors absorbing more than 95% of the injected photons over a wavelength range of several hundred nm can be designed. We propose a detector design making use of GaN/AlN waveguides, since these materials allow lattice-matched epitaxial deposition of Nb(Ti)N films and are transparent on a very wide wavelength range.
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| 2. |
- Olmedo, Miguel Iglesias, et al.
(författare)
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Chirp investigation in EMLs towards frequency shift keying modulation
- 2014
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Ingår i: Asia Communications and Photonics Conference 2014. - Washington, D.C. : OSA.
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Konferensbidrag (refereegranskat)abstract
- This paper presents a chirp modeling and experimental results that support our vision of enabling frequency shift keying (FSK) exploiting the chirp effect in externally modulated lasers (EMLs).
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| 3. |
- Pang, Xiaodan, 1986-, et al.
(författare)
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100 Gbit/s hybrid optical fiber-wireless link in the W-band (75–110 GHz)
- 2011
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 19:25, s. 24944-24949
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Tidskriftsartikel (refereegranskat)abstract
- We experimentally demonstrate an 100 Gbit/s hybrid optical fiber-wireless link by employing photonic heterodyning up-conversion of optical 12.5 Gbaud polarization multiplexed 16-QAM baseband signal with two free running lasers. Bit-error-rate performance below the FEC limit is successfully achieved for air transmission distances up to 120 cm.
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| 4. |
- Pang, Xiaodan, 1986-, et al.
(författare)
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25 Gbit/s QPSK Hybrid Fiber-Wireless Transmission in the W-Band (75–110 GHz) With Remote Antenna Unit for In-Building Wireless Networks
- 2012
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Ingår i: IEEE Photonics Journal. - : IEEE. - 1943-0655. ; 4:3, s. 691-698
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we demonstrate a photonic up-converted 25 Gbit/s fiber-wireless quadrature phase shift-keying (QPSK) data transmission link at the W-band (75-110 GHz). By launching two free-running lasers spaced at 87.5 GHz into a standard single-mode fiber (SSMF) at the central office, a W-band radio-over-fiber (RoF) signal is generated and distributed to the remote antenna unit (RAU). One laser carries 12.5 Gbaud optical baseband QPSK data, and the other acts as a carrier frequency generating laser. The two signals are heterodyne mixed at a photodetector in the RAU, and the baseband QPSK signal is transparently up-converted to the W-band. After the wireless transmission, the received signal is first down-converted to an intermediate frequency (IF) at 13.5 GHz at an electrical balanced mixer before being sampled and converted to the digital domain. A digital-signal-processing (DSP)-based receiver is employed for offline digital down-conversion and signal demodulation. We successfully demonstrate a 25 Gbit/s QPSK wireless data transmission link over a 22.8 km SSMF plus up to 2.13 m air distance with a bit-error-rate performance below the 2 x 10(-3) forward error correction (FEC) limit. The proposed system may have the potential for the integration of the in-building wireless networks with the fiber access networks, e. g., fiber-to-the-building (FTTB).
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| 5. |
- Vardakas, J. S., et al.
(författare)
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Towards high capacity and low latency backhauling in 5G : The 5G STEP-FWD vision
- 2017
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Ingår i: 2017 19th International Conference on Transparent Optical Networks (ICTON). - : IEEE Computer Society. - 9781538608586
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Konferensbidrag (refereegranskat)abstract
- This paper presents the vision of the 5G STEP-FWD project, funded by the European Commission, with the objective to propose a novel optical-wireless networking solution for the provision of high speed connectivity to end users. The features of the new architecture, based on the utilization of Ultra-Dense Wavelength Division Multiplexing Passive Optical Networks as the backhaul network, providing access to hyper dense mmWave networks, are presented in detail. Moreover, the research challenges to meet the 5G requirements in terms of low latency, spectral and energy efficiency are highlighted, followed by the description of way the project 5G STEP-FWD is going to address them.
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