Generalized Bloch wave analysis for fiber and waveguide gratings

We have developed a generalized Bloch wave approach for the analysis of aperiodic gratings. This method yields both a macroscopic (i.e., reflection or transmission coefficient) as well as a microscopic (i.e., dispersion diagram and microstructure of the propagating internal field) characterization of fiber and waveguide aperiodic gratings

Formula for two-carrier intermodulation distortion in wavelength converted subcarrier multiplexed signals via cross gain modulation

We present, for the first time to our knowledge, closed expression for the computation of the harmonic and intermodulation distortions that appear on a wavelength converted two-tone subcarrier modulation (SCM) signal via cross gain modulation

Harmonic distortion in microwave photonic filters

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.20.008871 . Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under lawWe present a theoretical and experimental analysis of nonlinear microwave photonic filters. Far from the conventional condition of low modulation index commonly used to neglect high-order terms, we have analyzed the harmonic distortion involved in microwave photonic structures with periodic and non-periodic frequency responses. We show that it is possible to design microwave photonic filters with reduced harmonic distortion and high linearity even under large signal operation. © 2012 Optical Society of America.The authors wish to acknowledge the financial support given by the Research Excellency Award Program GVA PROMETEO 2008/09 and the FEDER Program "Instrumentacion Avanzada para Comunicaciones Opticas" with reference UPVOV08-3E-008.Rius Mercado, M.; Mora Almerich, J.; Bolea Boluda, M.; Capmany Francoy, J. (2012). Harmonic distortion in microwave photonic filters. Optics Express. 20(8):8871-8876. doi:10.1364/OE.20.008871S88718876208Capmany, J., & Novak, D. (2007). Microwave photonics combines two worlds. Nature Photonics, 1(6), 319-330. doi:10.1038/nphoton.2007.89Yao, J. (2009). Microwave Photonics. Journal of Lightwave Technology, 27(3), 314-335. doi:10.1109/jlt.2008.2009551Capmany, J., Ortega, B., & Pastor, D. (2006). A tutorial on microwave photonic filters. Journal of Lightwave Technology, 24(1), 201-229. doi:10.1109/jlt.2005.860478Minasian, R. A., Alameh, K. E., & Chan, E. H. W. (2001). Photonics-based interference mitigation filters. IEEE Transactions on Microwave Theory and Techniques, 49(10), 1894-1899. doi:10.1109/22.954804Bolea, M., Mora, J., Ortega, B., & Capmany, J. (2010). Photonic arbitrary waveform generation applicable to multiband UWB communications. Optics Express, 18(25), 26259. doi:10.1364/oe.18.026259Capmany, J., Pastor, D., & Ortega, B. (1999). New and flexible fiber-optic delay-line filters using chirped Bragg gratings and laser arrays. IEEE Transactions on Microwave Theory and Techniques, 47(7), 1321-1326. doi:10.1109/22.775473Mora, J., Ortega, B., Capmany, J., Cruz, J., Andres, M., Pastor, D., & Sales, S. (2002). Automatic tunable and reconfigurable fiberoptic microwave filters based on a broadband optical source sliced by uniform fiber Bragg gratings. Optics Express, 10(22), 1291. doi:10.1364/oe.10.001291Capmany, J., Mora, J., Ortega, B., & Pastor, D. (2005). Microwave photonic filters using low-cost sources featuring tunability, reconfigurability and negative coefficients. Optics Express, 13(5), 1412. doi:10.1364/opex.13.001412Huang, T. X. H., Yi, X., & Minasian, R. A. (2011). Single passband microwave photonic filter using continuous-time impulse response. Optics Express, 19(7), 6231. doi:10.1364/oe.19.006231Dai, Y., & Yao, J. (2008). Nonuniformly-spaced photonic microwave delayline filter. Optics Express, 16(7), 4713. doi:10.1364/oe.16.004713Mora, J., Ortega, B., Diez, A., Cruz, J. L., Andres, M. V., Capmany, J., & Pastor, D. (2006). Photonic microwave tunable single-bandpass filter based on a Mach-Zehnder interferometer. Journal of Lightwave Technology, 24(7), 2500-2509. doi:10.1109/jlt.2006.874652Marcuse, D. (1980). Pulse distortion in single-mode fibers. Applied Optics, 19(10), 1653. doi:10.1364/ao.19.00165

Optical processing, Power response of a modulated general optical system

Optical processing: Power response of a modulated general optical syste

Ultra-Wideband pulses generation by means of incoherent optical processing compatible with radio-over-fibre systems

A technique for UWB pulses generation based on incoherent optical signal processing through a dispersive element is proposed and experimentally demonstrated. The generated waveform is given by the optical signal power distribution. Therefore, waveform reconfigurability is achieved by the proper control of the incoherent optical signal power distribution. UWB pulses generation have been experimentally demonstrated by means of the synthesis of monocycle and doublet waveforms using an optical channel selector to control the optical signal power distribution. Moreover, for wireless communications, the complete control on the waveform permits to fulfil the FCC spectral requirements and thus an increasing of the UWB radio signals coverage area

Scalable High-Order UWB Pulse Generation Employing an FBG-Based Photonic Superstructure

In this letter, we propose and experimentally demonstrate a compact, flexible, and scalable ultrawideband (UWB) generator based on the merge of phase-to-intensity conversion and pulse shaping employing an fiber Bragg Grating-based superstructure. Our approach offers the capacity for generating high-order UWB pulses by means of the combination of various low-order derivatives. Moreover, the scheme permits the implementation of binary and multilevel modulation formats. Experimental measurements of the generated UWB pulses, in both time and frequency domain, are presented revealing efficiency and a proper fit in terms of Federal Communications Commission settled standards.This work was supported in part by the National Project under Grant TEC2010-21303-C04-02, Grant TEC2011-26642, and Grant TEC2014-58048-C2-2-P through the Ministerio de Economia y Competitividad and in part by the Fondo Europeo de Desarrollo Regional under Project UPVOV08-3E-008.Moreno, V.; Mora Almerich, J.; Muriel, M.; Capmany Francoy, J. (2015). Scalable High-Order UWB Pulse Generation Employing an FBG-Based Photonic Superstructure. IEEE Photonics Technology Letters. 27(20):2146-2149. doi:10.1109/LPT.2015.2454952S21462149272

Microwave Photonics: Current challenges towards widespread application

Microwave Photonics, a symbiotic field of research that brings together the worlds of optics and radio frequency is currently facing several challenges in its transition from a niche to a truly widespread technology essential to support the ever-increasing values for speed, bandwidth, processing capability and dynamic range that will be required in next generation hybrid access networks. We outline these challenges, which are the subject of the contributions to this focus issue

Generation of an UWB monocycle employing cross-phase modulation in a SOA-MZ interferometer

In the present article, an innovative approach for generation of an UWB monocycle is proposed and experimentally demonstrated. The proposed design features the combination of an interferometric device (SOA-Mach Zehnder interferometer) with an optical processor unit. The fusion of such components permits to generate, combine and customize UWB pulses. An optical pulse is used as pump signal and two optical carriers represent and the optical input of the system. The selection of a specific wavelength and therefore of a particular port provides the possibility of modifying the systems output pulse polarity. The capacity of transmitting several data sequence has been also evidenced

Software-defined universal microwave photonics processor

We propose, for the first time to our knowledge, a software-defined reconfigurable microwave photonics signal processor architecture that can be integrated on a chip and is capable of performing all the main functionalities by suitable programming of its control signals. The basic configuration is presented and a thorough end-to-end design model derived that accounts for the performance of the overall processor taking into consideration the impact and interdependencies of both its photonic and RF parts. We demonstrate the model versatility by applying it to several relevant application examples.The authors wish to acknowledge the financial support given by the Research Excellency Award Program GVA PROMETEO II/2013/012 and the FPI-UPV Ayudas de Investigacion y Desarrollo (PAID) Program from the Universitat Politecnica de Valencia.Pérez, D.; Gasulla Mestre, I.; Capmany Francoy, J. (2015). Software-defined universal microwave photonics processor. Optics Express. 23(11):14640-14654. https://doi.org/10.1364/OE.23.014640S1464014654231