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6157 6162 20 6 ; S ; This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.20.006157. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law We propose and experimentally demonstrate new architectures to realize multi-tap microwave photonic filters, based on the generation of a single or multiple dynamic Brillouin gratings in polarization maintaining fibers. The spectral range and selectivity of the proposed periodic filters is extensively tunable, simply by reconfiguring the positions and the number of dynamic gratings along the fiber respectively. In this paper, we present a complete analysis of three different configurations comprising a microwave photonic filter implementation: a simple notch-type Mach-Zehnder approach with a single movable dynamic grating, a multi-tap performance based on multiple dynamic gratings and finally a stationary grating configuration based on the phase modulation of two counter-propagating optical waves by a common pseudo-random bit sequence (PRBS). The authors wish to acknowledge the financial support of the European Community's Seventh Framework Programme (FP 7) project GOSPEL; the GVA PROMETEO 2008/092, Infraestructura FEDER UPVOV08-3E-008, the Plan Nacional I + D TEC2011-29120-C05-05, the Swiss National Science Foundation through project 200021-134546 and the EPFL Space Center, the Israeli Science Foundation (ISF), and the KAMIN program of the Chief Scientist Office, Israel Ministry of Industry, Trade and Labor. Sancho Durá, J.; Sales Maicas, S.; Primerov, N.; Chin, S.; Antman, Y.; Zadok, A.; Thevenaz, L. (2012). Tunable and reconfigurable multi-tap microwave photonic filter based on dynamic Brillouin gratings in fibers. Optics Express. 20(6):6157-6162. https://doi.org/10.1364/OE.20.006157 Seeds, A. J. (2002). Microwave ...

10519 10525 20 10 ; S ; This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.20.010519 . Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law [EN] We theoretically and experimentally compare the performance of two fully tunable phase shifter structures based on semiconductor optical amplifiers (SOA) by means of several figures of merit common to microwave photonic systems. A single SOA stage followed by a tailored notch filter is compared with a cascaded implementation comprising three SOA-based phase shifter stages. Attention is focused on the assessment of the RF net gain, noise figure and nonlinear distortion. Recommendations on the performance optimization of this sort of approaches are detailed. The authors wish to acknowledge the financial support of the European Commission Seventh Framework Programme (FP7) project GOSPEL; the GVA PROMETEO 2008/092, the Plan Nacional I + D TEC2011-29120-C05-05 and Infraestructura FEDER UPVOV08-3E-008. Sancho Durá, J.; Lloret Soler, JA.; Gasulla Mestre, I.; Sales Maicas, S.; Capmany Francoy, J. (2012). Figures of merit for microwave photonic phase shifters based on semiconductor optical amplifiers. Optics Express. 20(10):10519-10525. https://doi.org/10.1364/OE.20.010519

[EN] We experimentally demonstrate a novel technique to process broadband microwave signals, using all-optically tunable true time delay in optical fibers. The configuration to achieve true time delay basically consists of two main stages: photonic RF phase shifter and slow light, based on stimulated Brillouin scattering in fibers. Dispersion properties of fibers are controlled, separately at optical carrier frequency and in the vicinity of microwave signal bandwidth. This way time delay induced within the signal bandwidth can be manipulated to correctly act as true time delay with a proper phase compensation introduced to the optical carrier. We completely analyzed the generated true time delay as a promising solution to feed phased array antenna for radar systems and to develop dynamically reconfigurable microwave photonic filters. (C) 2010 Optical Society of America ; We acknowledge the support from the Swiss National Science Foundation through project 200020-121860 and the support from the European Union FP7 project GOSPEL. ; Chin, S.; Thevenaz, L.; Sancho Durá, J.; Sales Maicas, S.; Capmany Francoy, J.; Berger, P.; Bourderionnet, J. (2010). Broadband true time delay for microwave signal processing, using slow light based on stimulated Brillouin scattering in optical fibers. Optics Express. 18(21):22599-22613. https://doi.org/10.1364/OE.18.022599 ; S ; 22599 ; 22613 ; 18 ; 21 ; Capmany, J., & Novak, D. (2007). Microwave photonics combines two worlds. Nature Photonics, 1(6), 319-330. doi:10.1038/nphoton.2007.89 ; Dolfi, D., Joffre, P., Antoine, J., Huignard, J.-P., Philippet, D., & Granger, P. (1996). Experimental demonstration of a phased-array antenna optically controlled with phase and time delays. Applied Optics, 35(26), 5293. doi:10.1364/ao.35.005293 ; Yunqi Liu, Jianliang Yang, & Jianping Yao. (2002). Continuous true-time-delay beamforming for phased array antenna using a tunable chirped fiber grating delay line. IEEE Photonics Technology Letters, 14(8), 1172-1174. ...

1746 1752 29 12 ; S ; This paper was published in JOURNAL OF LIGHTWAVE TECHNOLOGY and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1109/JLT.2011.2135839. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law. [EN] Different optical filtering scenarios involving microwave photonic phase shifters based on semiconductor optical amplifiers are investigated numerically as well as experimentally with respect to noise performance. Investigations on the role of the modulation depth and number of elements in cascaded shifting stages are also carried out. Suppression of the noise level by more than 5 dB has been achieved in schemes based on band-pass optical filtering when three phase shifting stages are cascaded. This work was supported in part by the EU FP7 within project GOSPEL, the Excellency Award Programme GVA PROMETEO 2008/092 and the Plan Nacional I+D TEC 2007-68065-C03-01. Lloret Soler, JA.; Ramos Pascual, F.; Xue, W.; Sancho Durá, J.; Gasulla Mestre, I.; Sales Maicas, S.; Mork, J. (2011). The Influence of Optical Filtering on the Noise Performance of Microwave Photonic Phase Shifters Based on SOAs. Journal of Lightwave Technology. 29(12):1746-1752. https://doi.org/10.1109/JLT.2011.2135839

The availability of a tunable delay line with a chip-size footprint is a crucial step towards the full implementation of integrated microwave photonic signal processors. Achieving a large and tunable group delay on a millimetre-sized chip is not trivial. Slow light concepts are an appropriate solution, if propagation losses are kept acceptable. Here we use a low-loss 1.5 mm-long photonic crystal waveguide to demonstrate both notch and band-pass microwave filters that can be tuned over the 0 50-GHz spectral band. The waveguide is capable of generating a controllable delay with limited signal attenuation (total insertion loss below 10 dB when the delay is below 70 ps) and degradation. Owing to the very small footprint of the delay line, a fully integrated device is feasible, also featuring more complex and elaborate filter functions. ; This work was funded by the European Union under the project GOSPEL (grant 219299) and by the Valencian Government (Prometeo GVA 2008-92). We thank S. Hughes and P. Lalanne for enlightening discussion about the impact of disorder in photonic crystal waveguides. ; Sancho Durá, J.; Bourderionnet, J.; Lloret Soler, JA.; Combrie, S.; Gasulla Mestre, I.; Xavier, S.; Sales Maicas, S. (2012). Integrable microwave filter based on a photonic crystal delay line. Nature Communications. 3:1-9. https://doi.org/10.1038/ncomms2092 ; S ; 1 ; 9 ; 3 ; Seeds, A. Microwave photonics. IEEE Trans. Microwave Theory Tech. 50, 877–887 (2002). ; Capmany, J. & Novak, D. Microwave photonics combines two worlds. Nat. Photon 1, 319–330 (2007). ; Yao, J. P. Microwave photonics. J. Lightwave Technol. 27, 314–335 (2009). ; See special technology focus on microwave photonics. Nat. Photon 5, 723–736 (2011). ; Capmany, J., Ortega, B. & Pastor, D. A tutorial on microwave photonic filters. J. Lightwave. Technol. 24, 201–229 (2006). ; Long, J. et al. A tunable microstrip bandpass filter with two independently adjustable transmission zeros. IEEE Microw. Wireless Compon. Lett. 21, 74–76 (2011). ; Velez, A. et al. ...