Few-mode fiber true time delay lines for distributed radiofrequency signal processing

[EN] We report, for the first time to our knowledge. distributed radiofrequency signal processing built upon true time delay operation on a step-index few-mode fiber. Two 3-sample configurations with different time delay properties are implemented over the same 60-meter 4-LP-mode fiber link. The inscription of a long period grating at a specific fiber position converts part of the LP01 mode into the LP02, permitting sample time delay engineering. Delay line performance is experimentally demonstrated when applied to radiofrequency signal filtering. example of fiber-distributed processing functionality exhibiting one order or magnitude gain in terms of compactness. (C) 2018 Optical Society of America America under the terms of the OSA Open Access Publishing AgreementH2020 European Research Council (ERC) (Consolidator Grant 724663); Spanish MINECO (TEC2014-60378-C2-1-R and TEC2016-80150-R projects, BES-2015-073359 scholarship for S. Garcia, Ramon y Cajal fellowship RYC-2014-16247 for I. Gasulla).© 2018 Optical Society of America. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibitedGuillem-Cogollos, R.; García-Cortijo, S.; Madrigal-Madrigal, J.; Barrera Vilar, D.; Gasulla Mestre, I. (2018). Few-mode fiber true time delay lines for distributed radiofrequency signal processing. Optics Express. 26(20):25761-25768. https://doi.org/10.1364/OE.26.025761S2576125768262