Monitoring temperature and vibration in a long weak grating array with short-pulse generation using a compact gain-switching laser diode module

© 2019 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 prohibited.[EN] Quasi-distributed temperature sensing and single point vibration sensing were performed. Ultrashort pulses generated by a gain-switching laser were used to interrogate a fiber Bragg gratings (FBG) array sensor. Temperature changes were measured down to 1 degrees C with sub-centimeter spatial resolution. The advantages of our fast interrogation setup were exploited, as the higher frequency limit of a dynamic measure that can be sensed is limited by the time needed to generate the optical pulse and to acquire the data from the sensor. The experimental approach described in this paper can sense mechanical vibrations up to a frequency of 245 kHz and a strain resolution as low as 1.2 mu epsilon.H2020 Marie Sklodowska-Curie Actions (MSCA-ITN-ETN-722509); Ministerio de Economia y Competitividad (DIMENSION TEC2017 88029-R); Generalitat Valenciana (PROMETEO 2017/103).Sartiano, D.; Sales Maicas, S. (2019). Monitoring temperature and vibration in a long weak grating array with short-pulse generation using a compact gain-switching laser diode module. Optics Express. 27(26):38661-38669. https://doi.org/10.1364/OE.379106S38661386692726Tosi, D. (2017). Review and Analysis of Peak Tracking Techniques for Fiber Bragg Grating Sensors. Sensors, 17(10), 2368. doi:10.3390/s17102368Mihailov, S. J. (2012). Fiber Bragg Grating Sensors for Harsh Environments. Sensors, 12(2), 1898-1918. doi:10.3390/s120201898Chan, P. K. C., Jin, W., Gong, J. M., & Demokan, N. S. (1999). Multiplexing of fiber Bragg grating sensors using a FMCW technique. IEEE Photonics Technology Letters, 11(11), 1470-1472. doi:10.1109/68.803082Pastor-Graells, J., Martins, H. F., Garcia-Ruiz, A., Martin-Lopez, S., & Gonzalez-Herraez, M. (2016). Single-shot distributed temperature and strain tracking using direct detection phase-sensitive OTDR with chirped pulses. Optics Express, 24(12), 13121. doi:10.1364/oe.24.013121Martins, H. F., Martin-Lopez, S., Corredera, P., Filograno, M. L., Frazao, O., & Gonzalez-Herraez, M. (2013). Coherent Noise Reduction in High Visibility Phase-Sensitive Optical Time Domain Reflectometer for Distributed Sensing of Ultrasonic Waves. Journal of Lightwave Technology, 31(23), 3631-3637. doi:10.1109/jlt.2013.2286223Ou, Y., Zhou, C., Qian, L., Fan, D., Cheng, C., & Guo, H. (2015). Large-capacity multiplexing of near-identical weak fiber Bragg gratings using frequency-shifted interferometry. Optics Express, 23(24), 31484. doi:10.1364/oe.23.031484Hervas, J., Barrera, D., Madrigal, J., & Sales, S. (2018). Microwave Photonics Filtering Interrogation Technique Under Coherent Regime For Hot Spot Detection on a Weak FBGs Array. Journal of Lightwave Technology, 36(4), 1039-1045. doi:10.1109/jlt.2018.2793161Ricchiuti, A. L., Hervás, J., & Sales, S. (2016). [INVITED] Cascade FBGs distributed sensors interrogation using microwave photonics filtering techniques. Optics & Laser Technology, 77, 144-150. doi:10.1016/j.optlastec.2015.09.003Nonaka, K., Mizuno, H., Song, H., Kitaoka, N., & Otani, A. (2008). Low-Time-Jitter Short-Pulse Generator Using Compact Gain-Switching Laser Diode Module With Optical Feedback Fiber Line. Japanese Journal of Applied Physics, 47(8), 6754-6756. doi:10.1143/jjap.47.6754Cusano, A., Cutolo, A., Nasser, J., Giordano, M., & Calabrò, A. (2004). Dynamic strain measurements by fibre Bragg grating sensor. Sensors and Actuators A: Physical, 110(1-3), 276-281. doi:10.1016/j.sna.2003.10.031Takahashi, N., Yoshimura, K., & Takahashi, S. (2001). Fiber Bragg Grating Vibration Sensor Using Incoherent Light. Japanese Journal of Applied Physics, 40(Part 1, No. 5B), 3632-3636. doi:10.1143/jjap.40.3632Tsuda, H. (2010). Fiber Bragg grating vibration-sensing system, insensitive to Bragg wavelength and employing fiber ring laser. Optics Letters, 35(14), 2349. doi:10.1364/ol.35.002349Lau, K. Y. (1988). Gain switching of semiconductor injection lasers. Applied Physics Letters, 52(4), 257-259. doi:10.1063/1.9948

Spot events detection along a large scale sensor based on ultra weak FBGs using time-frequency analysis

[EN] A simple scheme for interrogating a 5 m-long photonics device and its potential applications to quasi-distributed fiber sensing is proposed. The sensor consists of an array of 500 identical very weak fiber Bragg gratings (FBGs). The gratings are 9 mm-long and have been serially written in cascade along a single optical fiber. The measurement system is based on a combination of optical time domain reflectrometry (OTDR) and frequency scanning of the interrogating pulse. The time-frequency analysis is performed by launching an optical pulse into the sensor and by retrieving and analyzing the back-reflected signal. The measurement of the temperature, length and position of spot events along the sensors is demonstrated, with good accuracy. As both spatial and temperature resolution of the method depend on the input pulse duration, the system performance can be controlled and optimized by properly choosing the temporal duration of the interrogating pulse. A spatial resolution of 9 mm (ultimately dictated by one grating length) has been obtained with an 80 ps optical pulse; while a temperature resolution of less than 0.42 K has been demonstrated using a 500 ps incident pulse. The sensor proposed proves to be simple, robust, polarization insensitive and alleviates the instrumentation complexity for distributed sensing applications.Ministerio de Educacion, Cultura y Deporte; Ministerio de Economia y Competitividad (TEC2014-60378-C2-1-R); Generalitat Valenciana (GRISOLIA/2013/034); Research Excellency Award Program (GVA PROMETEO 2013/012).Ricchiuti, AL.; Sales Maicas, S. (2016). Spot events detection along a large scale sensor based on ultra weak FBGs using time-frequency analysis. Applied Optics. 55(5):1054-1060. https://doi.org/10.1364/AO.55.001054S1054106055

Regenerated Fiber Bragg Gratings in Multicore Fiber for Multi-parameter Sensing

© 2020 IEEE. Personal use of this material is permitted. Permissíon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisíng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] Multiple regenerated fiber Bragg gratings were inscribed in all the cores of a seven-core fiber in order to develop a multi-parameter sensor designed to operate at high temperatures. We experimentally showed the possibility of measuring strains of up to 1200 mu epsilon, curvatures from 0 degrees to 360 degrees and temperatures up to 1000 degrees C, with a maximum curvature magnitude of at least 4.6 m(-1) and a maximum sensibility of 96 pm/m(-1).This work was supported in part by the Spanish Ministry of Economy and Competitiveness under the DIMENSION TEC2017 88029-R Project and in part by the Generalitat Valenciana by the PROMETEO 2017/103 Research Excellency Award and IDI/FEDER/2018 GVA Infraestructura. The work of J. Madrigal was supported by a Universitat Politecnica de Valencia scholarship PAID-01-18. The work of D. Barrera was supported by a Spanish MICINN Fellowship IJCI-2017-32476.Madrigal-Madrigal, J.; Barrera, D.; Sales Maicas, S. (2020). Regenerated Fiber Bragg Gratings in Multicore Fiber for Multi-parameter Sensing. IEEE Journal of Selected Topics in Quantum Electronics. 26(4):1-6. https://doi.org/10.1109/JSTQE.2019.2958998S1626

Sub-cm Temperature Monitoring of 500 Weak Gratings Array Through Chirped Ultra-Short Light Pulses

© 2019 Optical Society of America]. Users may use, reuse, and build upon the article, or use the article for text or data mining, so long as such uses are for non-commercial purposes and appropriate attribution is maintained. All other rights are reserved.[EN] We developed a temperature quasi-distributed sensing system interrogating a 500 weak fiber Bragg gratings (FBGs) array of 5 meters. It was possible to sense temperature changes down to 1°C with sub-centimeter spatial resolution.This research was supported by FINESSE project, funded by the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska -Curie Action grant agreement n° 722509. It was also supported by the Ministry of Economy and Competitiveness project DIMENSION TEC2017 and by the Generalitat Valenciana project PROMETEO 2017/017.Sartiano, D.; Madrigal-Madrigal, J.; Sales Maicas, S. (2019). Sub-cm Temperature Monitoring of 500 Weak Gratings Array Through Chirped Ultra-Short Light Pulses. OSA. 1-2. http://hdl.handle.net/10251/180694S1

Multipoint two-dimensional curvature optical fiber sensor based on a non-twisted homogeneous four-core fiber

We have implemented a multipoint two-dimensional curvature optical fiber sensor based on a non-twisted homogeneous four-core fiber. A theoretical approach to model the mechanical behavior of these fibers under curvature conditions has been developed. Two shape sensors composed of an array of FBGs inscribed in the four-core fiber have been implemented to corroborate the theoretical analysis with the experimental results. The characterization of the proposed shape sensors showed their ability to measure the curvature radius, the curvature direction and any external applied force relate d to both uniform and non-uniform curvatures with high accuracy.Barrera Vilar, D.; Gasulla Mestre, I.; Sales Maicas, S. (2015). Multipoint two-dimensional curvature optical fiber sensor based on a non-twisted homogeneous four-core fiber. Journal of Lightwave Technology. 33(12):2445-2450. doi:10.1109/JLT.2014.2366556S24452450331

Tilted fiber Bragg gratings in multicore optical fibers for optical sensing

[EN] We have inscribed a tilted fiber Bragg grating (TFBG) in selected cores of a multicore optical fiber. The presence of the TFBG permits to couple light from the incident guided mode to the cladding modes and to the neighbor cores and this interaction can be used for optical sensing. We have considered to measure different magnitudes: strain, curvature magnitude and direction and external refractive index. The curvature results show a linear dependence of the maximum crosstalk with the curvature magnitude with a sensitivity of 2.5dB/m-1 as the curvature magnitude increases and at the same time a wavelength shift of 70pm/m-1. Changes in the external refractive index gradually vanishes the cladding modes resonances and the crosstalk between the different cores obtaining a reduction of the 90% of the optical spectra integral area for refractive indexes between 1.398 to 1.474.Generalitat Valenciana (APOSTD/2016/015, GVA PROMETEO 2013/012); Ministerio de Economia y Competitividad (MINECO) (TEC2014-60378-C2-1-R).Barrera Vilar, D.; Madrigal-Madrigal, J.; Sales Maicas, S. (2017). Tilted fiber Bragg gratings in multicore optical fibers for optical sensing. Optics Letters. 42(7):1460-1463. doi:10.1364/OL.42.001460S14601463427Flockhart, G. M. H., MacPherson, W. N., Barton, J. S., Jones, J. D. C., Zhang, L., & Bennion, I. (2003). Two-axis bend measurement with Bragg gratings in multicore optical fiber. Optics Letters, 28(6), 387. doi:10.1364/ol.28.000387Fender, A., MacPherson, W. N., Maier, R. R. J., Barton, J. S., George, D. S., Howden, R. I., … Bennion, I. (2008). Two-Axis Temperature-Insensitive Accelerometer Based on Multicore Fiber Bragg Gratings. IEEE Sensors Journal, 8(7), 1292-1298. doi:10.1109/jsen.2008.926878Barrera, D., Gasulla, I., & Sales, S. (2015). Multipoint Two-Dimensional Curvature Optical Fiber Sensor Based on a Nontwisted Homogeneous Four-Core Fiber. Journal of Lightwave Technology, 33(12), 2445-2450. doi:10.1109/jlt.2014.2366556Corres, J. M., Arregui, F. J., & Matías, I. R. (2007). Sensitivity optimization of tapered optical fiber humidity sensors by means of tuning the thickness of nanostructured sensitive coatings. Sensors and Actuators B: Chemical, 122(2), 442-449. doi:10.1016/j.snb.2006.06.008Barrera, D., Villatoro, J., Finazzi, V. P., Cárdenas-Sevilla, G. A., Minkovich, V. P., Sales, S., & Pruneri, V. (2010). Low-Loss Photonic Crystal Fiber Interferometers for Sensor Networks. Journal of Lightwave Technology, 28(24), 3542-3547. doi:10.1109/jlt.2010.2090861Kisała, P., Harasim, D., & Mroczka, J. (2016). Temperature-insensitive simultaneous rotation and displacement (bending) sensor based on tilted fiber Bragg grating. Optics Express, 24(26), 29922. doi:10.1364/oe.24.029922Albert, J., Shao, L.-Y., & Caucheteur, C. (2012). Tilted fiber Bragg grating sensors. Laser & Photonics Reviews, 7(1), 83-108. doi:10.1002/lpor.201100039Chen, C., Caucheteur, C., Mégret, P., & Albert, J. (2007). The sensitivity characteristics of tilted fibre Bragg grating sensors with different cladding thicknesses. Measurement Science and Technology, 18(10), 3117-3122. doi:10.1088/0957-0233/18/10/s11Dong, X., Zhang, H., Liu, B., & Miao, Y. (2010). Tilted fiber Bragg gratings: Principle and sensing applications. Photonic Sensors, 1(1), 6-30. doi:10.1007/s13320-010-0016-xGuo, T., Liu, F., Guan, B.-O., & Albert, J. (2016). [INVITED] Tilted fiber grating mechanical and biochemical sensors. Optics & Laser Technology, 78, 19-33. doi:10.1016/j.optlastec.2015.10.007Cai, Z., Liu, F., Guo, T., Guan, B.-O., Peng, G.-D., & Albert, J. (2015). Evanescently coupled optical fiber refractometer based a tilted fiber Bragg grating and a D-shaped fiber. Optics Express, 23(16), 20971. doi:10.1364/oe.23.020971Gasulla, I., Barrera, D., Hervás, J., & Sales, S. (2017). Spatial Division Multiplexed Microwave Signal processing by selective grating inscription in homogeneous multicore fibers. Scientific Reports, 7(1). doi:10.1038/srep41727Gallagher, M., & Österberg, U. (1993). Time resolved 3.10 eV luminescence in germanium‐doped silica glass. Applied Physics Letters, 63(22), 2987-2989. doi:10.1063/1.110290Komukai, T., & Nakazawa, M. (1996). Fabrication of high-quality long-fiber Bragg grating by monitoring 3.1-eV radiation (400 nm) from GeO defects. IEEE Photonics Technology Letters, 8(11), 1495-1497. doi:10.1109/68.54156

Long Period Gratings in Multicore Optical Fibers for Directional Curvature Sensor Implementation

[EN] Multicore optical fibers are especially attractive for the fabrication of curvature and shape sensors due to the spatial distribution of the different cores. Fiber Bragg gratings have been used in the past for the implementation of these sensors, however, despite their inherent properties, they have a very limited sensitivity. In this paper, we study the use of long period gratings (LPGs) for the implementation of a directional curvature sensor. We inscribed a set of three different LPGs in a seven core optical fiber using a selective inscription technique. We inscribed a single LPG in the external cores and an array of three LPGs in the central core. We have characterized the proposed sensor for strain, torsion, and curvature magnitude and direction. The proposed sensor shows a linear response for curvature magnitudes from 0 to 1.77 m(-1) with a maximum curvature sensitivity of -4.85 nm/m(-1) and shows a near sinusoidal behavior in all the cores with curvature directions from 0 degrees to 360 degrees. The sensor shows a good insensitivity to strain. The torsion in the multicore optical fibers can be detected and measured using the maximum attenuation of the LPGs in the external cores.This work was supported in part by the Sistema Nacional de Garantia Juvenil under Grant PEJ-2014-A-75865 (Promocion de Empleo Joven e Implantacion de la Garantia Juvenil 2014, MINECO), in part by the Ministry of Economy and Competitiveness under Project TEC2014-60378-C2-1-R, in part by the FINESSE the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Action Grant 722509, and in part by the Generalitat Valenciana under Grant APOSTD/2016/015.Barrera Vilar, D.; Madrigal-Madrigal, J.; Sales Maicas, S. (2018). Long Period Gratings in Multicore Optical Fibers for Directional Curvature Sensor Implementation. Journal of Lightwave Technology. 36(4):1063-1068. https://doi.org/10.1109/JLT.2017.2764951S1063106836

(Invited) Cascade FBGs distributed sensors interrogation using microwave photonics filtering techniques

Systems to interrogate photonic sensors based on long fiber Bragg gratings (FBGs) are illustrated and experimentally validated. The FBGs-based devices are used as quasi-distributed sensors and have demonstrated their ability to detect and measure the precise location of several spot events. The principle of operation is based on a technique used to analyze microwave photonics (MWP) filters. The overall idea beyond this work has been borne out and demonstrated step by step starting from preliminary test that have led to the development of a very-long distributed sensor based on an array of 500 equal and weak FBGs. Firstly, we have demonstrated the feasibility of the MWP filtering technique to interrogate a 10 cm-long high reflectivity (&#8776;99%) FBG. Then, a pair of low-reflectivity (<6%) FBGs has been employed as sensing device. The latter has laid the foundation for the development and implementation of a 5 m-long fiber optic sensor based on 500 very weak FBGs. Spot events have been detected with a good spatial accuracy of less than 1 mm using a modulator and a photo-detector (PD) with a modest bandwidth of only 500 MHz. The simple proposed schemes result cost effective, intrinsically robust against environmental changes and easy to reconfigure.This work was support by the Accion Financiada por el Ministerio de Educacion, Cultura y Deporte within the framework of the Programa de Campus de Excelencia Internacional VLC/Campus, by the Spanish MINECO through projects TEC2014-60378-C2-1-R, by the Grant of the program SANTIAGO GRISOLIA (Grant number GRISOLIA/2013/034), and by the Research Excellency Award Program GVA PROMETEO 2013/012.Ricchiuti, AL.; Hervás-Peralta, J.; Sales Maicas, S. (2016). (Invited) Cascade FBGs distributed sensors interrogation using microwave photonics filtering techniques. Optics and Laser Technology. 77(3):144-150. https://doi.org/10.1016/j.optlastec.2015.09.003S14415077

Microwave photonics: Harnessing slow light

Slow-light techniques originally conceived for buffering high-speed digital optical signals now look set to play an important role in providing broadband phase and true time delays for microwave signals.The European project GOSPEL (Governing the Speed of Light) has had notable success in developing a suite of MWP devices.Capmany Francoy, J.; Gasulla Mestre, I.; Sales Maicas, S. (2011). Microwave photonics: Harnessing slow light. Nature Photonics. 5(12):731-733. https://doi.org/10.1038/nphoton.2011.290S73173351

Refractive Index and Temperature Sensing Using Inter-Core Crosstalk in Multicore Fibers

[EN] Multicore optical fibers are of great interest in the optical sensing field. Their core diversity and spatial distribution enable the development of sensing mechanisms that are not possible in single-core fibers. In this paper, we study the use of the inter-core crosstalk phenomena for the implementation of a surrounding refractive index (SRI) sensor. The selective inscription of a tilted fiber Bragg grating (TFBG) intentionally increases the inter-core crosstalk between the inscribed cores and makes it sensitive to the SRI. With this technique we simplify the measurement of the SRI and improve the identification and tracking of the excited cladding modes, as compared with the analysis of the transmission spectrum of a TFBG in single-core fibers. The proposed device is also sensitive to temperature. Temperature is obtained from the crosstalk wavelength shift with a measured sensitivity of 9.75 pm/degrees C. The SRI is obtained from the measurement of the crosstalk optical power. For increasing SRIs the cladding modes gradually fade, reducing the crosstalk optical power. We observed that the higher the tilt, the higher the sensor sensitivity. For a 7 degrees TFBG the SRI sensitivity obtained is -74.2 dB/RIU from 1.31 to 1.39 and -250.8 dB/RIU from 1.39 to 1.44.This work was supported in part by the Spanish Ministry of Economy and Competitiveness under the DIMENSION TEC2017 88029-R Project and in part by the Generalitat Valenciana by PROMETEO 2017/103 research excellency award and IDI/FEDER/2018 GVA Infraestructura. The work of J. Madrigal was supported by Universitat Politecnica de Valencia scholarship PAID-01-18. The work of D. Barrera was supported by Spanish MICINN fellowship IJCI-2017-32476.Madrigal-Madrigal, J.; Barrera Vilar, D.; Sales Maicas, S. (2019). Refractive Index and Temperature Sensing Using Inter-Core Crosstalk in Multicore Fibers. Journal of Lightwave Technology. 37(18):4703-4709. https://doi.org/10.1109/JLT.2019.2917629S47034709371