Aston Institute of Photonic Technologies

Birmingham, United Kingdom

Aston Institute of Photonic Technologies

Birmingham, United Kingdom
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PubMed | Vinča Institute of Nuclear Sciences, Aston Institute of Photonic Technologies, Moog and University of Belgrade
Type: Journal Article | Journal: Biomedical optics express | Year: 2014

In non-invasive ventilation, continuous monitoring of respiratory volumes is essential. Here, we present a method for the measurement of respiratory volumes by a single fiber-grating sensor of bending and provide the proof-of-principle by applying a calibration-test measurement procedure on a set of 18 healthy volunteers. Results establish a linear correlation between a change in lung volume and the corresponding change in a local thorax curvature. They also show good sensor accuracy in measurements of tidal and minute respiratory volumes for different types of breathing. The proposed technique does not rely on the air flow through an oronasal mask or the observation of chest movement by a clinician, which distinguishes it from the current clinical practice.


News Article | December 5, 2016
Site: phys.org

Scientists from Russia and the U.K. have developed an antenna that can aid in reducing sources of terahertz radiation down to the size of a fingertip. The antenna is a "sandwich" of semiconductor layers combined with quantum dots. The scientists demonstrated that such antennas provide a foundation for a new universal system capable of both transmitting and receiving terahertz radiation. Compact devices, operating at terahertz range, have applications in medicine and biology for tumor visualization and in the aerospace industry for high-speed communication systems. The study was published in Laser & Photonics Reviews. The terahertz range lies between infrared and microwave spectra. Terahertz radiation can penetrate living tissues, but unlike X-rays, is not ionizing and poses no health hazard. Therefore, medical practitioners could benefit immensely from compact terahertz scanners that can obtain pictures of tissues in living organisms. Researchers from Aston University and ITMO University used quantum dots to develop an antenna that can significantly reduce the size of terahertz sources. The work was supported by scientists from the University of Strathclyde and University of Sheffield, as well as TeraVil Ltd company and Center for Physical Sciences and Technology in Vilnius. "It was a technological challenge," says the study's academic supervisor Edik Rafailov, professor at Aston Institute of Photonic Technologies and leading research associate at ITMO University. "We demonstrated that quantum dots are a good alternative for conventional semiconductors. This new technology gives us an opportunity to generate terahertz at room temperature. And potentially make terahertz devices compact and cheap." Today, terahertz generation relies on sources that involve conversion of infrared laser beam into terahertz. The transformation is carried out with intricate systems of waveguides, semiconductor crystals or diodes. The search for alternative ways of generating and detecting terahertz waves is still underway, but such devices remain bulky, expensive and operate only at low temperatures. The new antennas make it possible not only to use terahertz sources at room temperature, but also to miniaturize them. "We are able to create very compact sources of terahertz radiation the size of a fingertip," comments leading author of the paper Andrei Gorodetsky, researcher at the Department of Photonics and Optical Information Technology of ITMO University and research associate at Aston Institute of Photonic Technologies. "With the new antennas, we managed to remove the limitation associated with the narrow light spectrum that is used by current converts. This gives us an opportunity to combine the antennas with compact infrared lasers. Additionally, the antennas are 20 times more resistant to damage than typical semiconductor devices. Both factors allow us to incorporate the antenna into the laser instead of setting it apart." The researchers suggest that their findings can be used in high-speed communication systems and also in compact terahertz scanners, which would give dynamic imaging of deep skin layers, embryo development, brain processes, and scanning of internal organs or tumors. Terahertz radiation is not harmful, as it does not scatter too much in biological tissues. As a result, terahertz systems are more informative, sensitive and fast compared to their substitutes from other parts of electromagnetic spectrum. Explore further: Wearable terahertz scanning device for inspection of medical equipment and the human body More information: Ross R. Leyman et al. Quantum dot materials for terahertz generation applications, Laser & Photonics Reviews (2016). DOI: 10.1002/lpor.201500176


Ye N.,Tyndall National Institute | Gleeson M.R.,Tyndall National Institute | Sadiq M.U.,Tyndall National Institute | Roycroft B.,Tyndall National Institute | And 15 more authors.
Journal of Lightwave Technology | Year: 2015

Progress on advanced active and passive photonic components that are required for high-speed optical communications over hollow-core photonic bandgap fiber at wavelengths around 2 μm is described in this paper. Single-frequency lasers capable of operating at 10 Gb/s and covering a wide spectral range are realized. A comparison is made between waveguide and surface normal photodiodes with the latter showing good sensitivity up to 15 Gb/s. Passive waveguides, 90° optical hybrids, and arrayed waveguide grating with 100-GHz channel spacing are demonstrated on a large spot-size waveguide platform. Finally, a strong electro-optic effect using the quantum confined Stark effect in strain-balanced multiple quantum wells is demonstrated and used in a Mach-Zehnder modulator capable of operating at 10 Gb/s. © 2014 IEEE.


Giacoumidis E.,Aston Institute of Photonic Technologies | Aldaya I.,Monterrey Institute of Technology | Jarajreh M.A.,Northumbria University | Tsokanos A.,University of Plymouth | And 5 more authors.
IEEE Photonics Technology Letters | Year: 2014

A reconfigurable nonlinear equalizer (RNLE) based on inverse Volterra series transfer function is proposed for dual-polarization (DP) and multiband coherent optical orthogonal frequency-division multiplexing (OFDM) signals. It is shown that the RNLE outperforms by 2 dB the linear equalization in a 260-Gb/s DP-OFDM system at 1500 km. The RNLE improves the tolerance to inter/intraband nonlinearities, being independent on polarization tributaries, modulation format, signal bit rate, subcarrier number, and distance. © 1989-2012 IEEE.


Jarajreh M.A.,Northumbria University | Giacoumidis E.,Aston Institute of Photonic Technologies | Aldaya I.,Monterrey Institute of Technology | Le S.T.,Aston Institute of Photonic Technologies | And 3 more authors.
IEEE Photonics Technology Letters | Year: 2015

We propose a novel low-complexity artificial neural network (ANN)-based nonlinear equalizer (NLE) for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) and compare it with the recent inverse Volterra-series transfer function (IVSTF)-based NLE over up to 1000 km of uncompensated links. Demonstration of ANN-NLE at 80-Gb/s CO-OFDM using 16-quadrature amplitude modulation reveals a Q-factor improvement after 1000-km transmission of 3 and 1 dB with respect to the linear equalization and IVSTF-NLE, respectively. © 2014 IEEE.


Le S.T.,Aston Institute of Photonic Technologies | McCarthy M.E.,Aston Institute of Photonic Technologies | Suibhne N.M.,Aston Institute of Photonic Technologies | Ellis A.D.,Aston Institute of Photonic Technologies | Turitsyn S.K.,Aston Institute of Photonic Technologies
Journal of Lightwave Technology | Year: 2015

In this paper, we demonstrate a novel fiber nonlinearity compensation technique for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) systems based on the transmission of phase-conjugated pilots (PCPs). In this scheme, a portion of OFDM subcarriers (up to 50%) is transmitted with its phase conjugates, which is used at the receiver to estimate the nonlinear distortions in the respective subcarriers and other subcarriers, which are not accompanied by PCPs. Simulation and experimental results show that by varying the PCP overhead, a performance improvement up to 4 dB can be achieved. In addition, the proposed technique can be effectively applied in both single polarization and polarization-division multiplexed systems, in both single channel and wavelength-division multiplexing systems, thus, offering highest flexibility in implementations. © 2015 IEEE.


Walsh A.J.,Dublin City University | Mountjoy J.,Electric Ireland | Shams H.,University College London | Fagan A.,Electric Ireland | And 2 more authors.
Journal of Lightwave Technology | Year: 2015

A dual polarization doubly differential phase shift keying coherent optical packet receiver that is robust against frequency offset transients and polarization demultiplexing problems is described in detail for energy efficient reconfigurable networks. Its performance is not affected by large frequency offsets. This leads to greatly reduced waiting times compared with previous coherent optical packet receivers, which in turn can significantly increase throughput in the coherent optical packet switched networks. © 2015 IEEE.


Le S.T.,Aston Institute of Photonic Technologies | McCarthy M.E.,Aston Institute of Photonic Technologies | Suibhne N.M.,Aston Institute of Photonic Technologies | Al-Khateeb M.A.Z.,Aston Institute of Photonic Technologies | And 4 more authors.
Journal of Lightwave Technology | Year: 2015

In this paper, we demonstrate through computer simulation and experiment a novel subcarrier coding scheme combined with pre-electrical dispersion compensation (pre-EDC) for fiber nonlinearity mitigation in coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. As the frequency spacing in CO-OFDM systems is usually small (tens of MHz), neighbouring subcarriers tend to experience correlated nonlinear distortions after propagation over a fiber link. As a consequence, nonlinearity mitigation can be achieved by encoding and processing neighbouring OFDM subcarriers simultaneously. Herein, we propose to adopt the concept of dual phase conjugated twin wave for CO-OFDM transmission. Simulation and experimental results show that this simple technique combined with 50% pre-EDC can effectively offer up to 1.5 and 0.8 dB performance gains in CO-OFDM systems with BPSK and QPSK modulation formats, respectively. © 1983-2012 IEEE.


Thai Le S.,Aston Institute of Photonic Technologies | McCarthy M.E.,Aston Institute of Photonic Technologies | Suibhne N.M.,Aston Institute of Photonic Technologies | Giacoumidis E.,Aston Institute of Photonic Technologies | And 3 more authors.
IEEE Photonics Technology Letters | Year: 2014

In this letter, we experimentally study the statistical properties of a received QPSK modulated signal and compare various bit error rate (BER) estimation methods for coherent optical orthogonal frequency division multiplexing transmission. We show that the statistical BER estimation method based on the probability density function of the received QPSK symbols offers the most accurate estimate of the system performance. © 2014 IEEE.


Le S.T.,Aston Institute of Photonic Technologies | Kanesan T.,Aston Institute of Photonic Technologies | Giacoumidis E.,Aston Institute of Photonic Technologies | Doran N.J.,Aston Institute of Photonic Technologies | Ellis A.D.,Aston Institute of Photonic Technologies
IEEE Photonics Technology Letters | Year: 2014

In this letter, a novel phase noise estimation scheme has been proposed for coherent optical orthogonal frequency division multiplexing systems, the quasi-pilot-aided method. In this method, the phases of transmitted pilot subcarriers are deliberately correlated to the phases of data subcarriers. Accounting for this correlation in the receiver allows the required number of pilots needed for a sufficient estimation and compensation of phase noise to be reduced by a factor of 2 in comparison with the traditional pilot-aided phase noise estimation method. We carried out numerical simulation of a 40 Gb/s single polarization transmission system, and the outcome of the investigation indicates that by applying quasi-pilot-aided phase estimation, only four pilot subcarriers are needed for effective phase noise compensation. © 2014 IEEE.

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