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A complex-valued multi-tap tunable microwave photonic filter based on single silicon-on-insulator microring resonator is presented. The degree of tunability of the approach involving two, three and four taps is theoretical and experimentally characterized, respectively. The constraints of exploiting the optical phase transfer function of a microring resonator aiming at implementing complex-valued multi-tap filtering schemes are also reported. The trade-off between the degree of tunability without changing the free spectral range and the number of taps is studied in-depth. Different window based scenarios are evaluated for improving the filter performance in terms of the side-lobe level. waveguide band-stop and band-pass filters based on open split ring resonators and open complementary split ring resonators," IEE Proc.

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A novel radiofrequency ablation catheter has been developed with integrated custom designed optics, enabling real-time monitoring of radiofrequency ablation procedures through polarization-sensitive optical coherence reflectometry. The optics allow for proper tissue illumination through a view-port machined in the catheter tip, thus providing lesion depth control over the RF ablation treatment. The system was verified in an in-vitro model of swine myocardium. Optical performance and thermal stability was confirmed after more than 25 procedures, without any damage to the optical assembly induced by thermal stress or material degradation. The use of this catheter in RF ablation treatments may make possible to assess lesion depth during therapy, thus translating into a reduction of potential complications on the procedure.

A fully tunable microwave photonic phase shifter involving a single semiconductor optical amplifier (SOA) is proposed and demonstrated. 360° microwave phase shift has been achieved by tuning the carrier wavelength and the optical input power injected in an SOA while properly profiting from the dispersion feature of a conveniently designed notch filter. It is shown that the optical filter can be advantageously employed to switch between positive and negative microwave phase shifts. Numerical calculations corroborate the experimental results showing an excellent agreement.

A recent analysis of the Fermi Large Area Telescope data provided evidence for a high-intensity emission of high-energy gamma rays with a E −2 spectrum from two large areas, spanning 50 • above and below the Galactic centre (the "Fermi bubbles"). A hadronic mechanism was proposed for this gamma-ray emission making the Fermi bubbles promising source candidates of high-energy neutrino emission. In this work Monte Carlo simulations regarding the detectability of high-energy neutrinos from the Fermi bubbles 4 with the future multi-km 3 neutrino telescope KM3NeT in the Mediterranean Sea are presented. Under the hypothesis that the gamma-ray emission is completely due to hadronic processes, the results indicate that neutrinos from the bubbles could be discovered in about one year of operation, for a neutrino spectrum with a cutoff at 100 TeV and a detector with about 6 km 3 of instrumented volume. The effect of a possible lower cutoff is also considered.