L. Schenato, Pedro J. Vidal-Moreno, M. Santagiustina, A. Galtarossa, L. Palmieri, E. Díez-Jiménez, S. Martín-López, M. González-Herráez
This paper introduces and numerically investigates a special optical fiber cable with zero temperature-induced phase shift. The cable structure consists of stacked layers of two materials with opportune mechanical, thermal, and geometrical properties. This structure allows adjusting the thermal-induced strain to the fiber, resulting in a broad tunability of the bare thermal expansion, including the negative range. By a proper choice of materials, the thickness of each layer, and the radius of the cable, the induced thermal strain can fully compensate for the thermo-optic effect, resulting in a complete temperature insensitivity of the phase shift. This cable may be of great interest in the sensing fields in all those applications where the temperature compensation is critical, such as in low-frequency distributed acoustic sensing. Moreover, it could be relevant for a wide range of telecom applications that require precise thermal control.
{"title":"Numerical modeling of a novel athermal fiber optic cable","authors":"L. Schenato, Pedro J. Vidal-Moreno, M. Santagiustina, A. Galtarossa, L. Palmieri, E. Díez-Jiménez, S. Martín-López, M. González-Herráez","doi":"10.1117/12.2679988","DOIUrl":"https://doi.org/10.1117/12.2679988","url":null,"abstract":"This paper introduces and numerically investigates a special optical fiber cable with zero temperature-induced phase shift. The cable structure consists of stacked layers of two materials with opportune mechanical, thermal, and geometrical properties. This structure allows adjusting the thermal-induced strain to the fiber, resulting in a broad tunability of the bare thermal expansion, including the negative range. By a proper choice of materials, the thickness of each layer, and the radius of the cable, the induced thermal strain can fully compensate for the thermo-optic effect, resulting in a complete temperature insensitivity of the phase shift. This cable may be of great interest in the sensing fields in all those applications where the temperature compensation is critical, such as in low-frequency distributed acoustic sensing. Moreover, it could be relevant for a wide range of telecom applications that require precise thermal control.","PeriodicalId":424244,"journal":{"name":"European Workshop on Optical Fibre Sensors","volume":"430 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122879021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Íñigo Corera, Javier Pradas, D. Leandro, M. Bravo Acha, M. López-Amo
In this work, it is presented an analysis of FBG arrays installed in a public road. The arrays were installed in a newly paved urban road and were monitored for more than one year. The study evidences the permanent deformation of the wearing course and the degradation of the reflected spectra of the sensors.
{"title":"One-year analysis of road condition using FBG arrays","authors":"Íñigo Corera, Javier Pradas, D. Leandro, M. Bravo Acha, M. López-Amo","doi":"10.1117/12.2679677","DOIUrl":"https://doi.org/10.1117/12.2679677","url":null,"abstract":"In this work, it is presented an analysis of FBG arrays installed in a public road. The arrays were installed in a newly paved urban road and were monitored for more than one year. The study evidences the permanent deformation of the wearing course and the degradation of the reflected spectra of the sensors.","PeriodicalId":424244,"journal":{"name":"European Workshop on Optical Fibre Sensors","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124264524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we proposed an in-fiber Mach-Zehnder temperature sensor based on a dual-core fiber (DCF) with one core as the sensing arm suspended in the centre fluidic channel of the DCF and the other core as the reference arm running eccentrically along the fiber. The fluidic channel was infiltrated with silicone oil. Temperature variations would change the refractive index of silicone oil and thus the effective index of the guided mode in the suspended core, thus shifting the interference spectra. The sensitivity of the sensor using a DCF infiltrated with ∼20 cm-long silicone oil was found to be as high as −1.42 nm/°C, comparable to those of the SPR fiber sensors and other interferometric sensors. The measuring range of the sensor was more than 120°C. The proposed sensor could be easily fabricated with good robustness and stability, which makes the sensor suitable for applications such as environment and architecture monitoring.
{"title":"Fiber optic Mach-Zehnder temperature sensor based on dual-core fiber","authors":"Shaoxin Ma, Yufei Zhang, Haiming Qiu, Chunyun Zhao, Xuehao Hu, H. Qu","doi":"10.1117/12.2678433","DOIUrl":"https://doi.org/10.1117/12.2678433","url":null,"abstract":"In this paper, we proposed an in-fiber Mach-Zehnder temperature sensor based on a dual-core fiber (DCF) with one core as the sensing arm suspended in the centre fluidic channel of the DCF and the other core as the reference arm running eccentrically along the fiber. The fluidic channel was infiltrated with silicone oil. Temperature variations would change the refractive index of silicone oil and thus the effective index of the guided mode in the suspended core, thus shifting the interference spectra. The sensitivity of the sensor using a DCF infiltrated with ∼20 cm-long silicone oil was found to be as high as −1.42 nm/°C, comparable to those of the SPR fiber sensors and other interferometric sensors. The measuring range of the sensor was more than 120°C. The proposed sensor could be easily fabricated with good robustness and stability, which makes the sensor suitable for applications such as environment and architecture monitoring.","PeriodicalId":424244,"journal":{"name":"European Workshop on Optical Fibre Sensors","volume":"2012 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125357157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optical fibers are often used as a medium for nonlinear optical processes, especially for frequency doubling or second harmonic generation (SHG). Obtaining efficient SHG requires phase matching, which is challenging to achieve with ultrashort laser pulses. For that purpose we study how specific optical fiber designs can facilitate said phase matching. In this report we show that multi-step index fibers, which can be considered as an approximation of graded index fibers, can provide for simultaneous modal phase matching (MPM) and group velocity matching (GVM). That leads to an efficient pulsed second harmonic generation in optical fiber, which will open new opportunities for fiber sensing domain as well, where bio-sensing, medical sensing and strain sensing can be in the target.
{"title":"Simultaneous modal phase- and group velocity matching in multiple step-index highly GeO2-doped optical fibers","authors":"A. Tishchenko, F. Berghmans, T. Baghdasaryan","doi":"10.1117/12.2680578","DOIUrl":"https://doi.org/10.1117/12.2680578","url":null,"abstract":"Optical fibers are often used as a medium for nonlinear optical processes, especially for frequency doubling or second harmonic generation (SHG). Obtaining efficient SHG requires phase matching, which is challenging to achieve with ultrashort laser pulses. For that purpose we study how specific optical fiber designs can facilitate said phase matching. In this report we show that multi-step index fibers, which can be considered as an approximation of graded index fibers, can provide for simultaneous modal phase matching (MPM) and group velocity matching (GVM). That leads to an efficient pulsed second harmonic generation in optical fiber, which will open new opportunities for fiber sensing domain as well, where bio-sensing, medical sensing and strain sensing can be in the target.","PeriodicalId":424244,"journal":{"name":"European Workshop on Optical Fibre Sensors","volume":"12643 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129852079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Monika Żuchowska, P. Marć, A. Pakuła, A. Kurzych, G. Stępniewski, R. Buczyński, L. Jaroszewicz
Polymer microtips manufactured at the end face of standard optical fibers have been used for effectively coupling with a selected antiresonant fibers (ARFs). Four tested ARFs had similar geometry, 7 capillaries placed around the central air core. It was shown how such coupling structure modified the ARFs spectral characteristics. Applying polymer microtip successfully excited additional bands. Illumination of the ARF with a microtip that operates as a microlens causes a change in numerical aperture and mode number.
{"title":"Spectral properties of selected antiresonant fibers coupled with standard optical fibers by means of polymer microtips","authors":"Monika Żuchowska, P. Marć, A. Pakuła, A. Kurzych, G. Stępniewski, R. Buczyński, L. Jaroszewicz","doi":"10.1117/12.2678306","DOIUrl":"https://doi.org/10.1117/12.2678306","url":null,"abstract":"Polymer microtips manufactured at the end face of standard optical fibers have been used for effectively coupling with a selected antiresonant fibers (ARFs). Four tested ARFs had similar geometry, 7 capillaries placed around the central air core. It was shown how such coupling structure modified the ARFs spectral characteristics. Applying polymer microtip successfully excited additional bands. Illumination of the ARF with a microtip that operates as a microlens causes a change in numerical aperture and mode number.","PeriodicalId":424244,"journal":{"name":"European Workshop on Optical Fibre Sensors","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124991830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. K. Chaudhary, Hariharan Manoharan, K. Swain, N. Madaboosi, V. Sai
This study investigates the use of U-shaped cladded plastic optical fiber (POF) and glass optical fiber (GOF) probes for refractive index (RI) sensing as they allow a simple one-step fabrication process. The RI sensitivity of the U-shaped cladded POF probes were evaluated in narrow (1.333 to 1.348, increment of 0.003 RI) and intermediate RI ranges (1.34 to 1.39, increment of 0.01 RI). No considerable improvement or drop was observed. However, the U-shaped silica cladded GOF showed 1.3 and 1.54 -fold improvement in the RI sensitivity in comparison to the decladded probes in the narrow and intermediate RI range respectively. The highest sensitivities for cladded POF and GOF probes in the intermediate RI range were 4.7 and 10.8 ΔA530 nm/ΔRIU respectively.
{"title":"Investigations on cladded U-shaped fiber optic sensors for refractive index measurements","authors":"R. K. Chaudhary, Hariharan Manoharan, K. Swain, N. Madaboosi, V. Sai","doi":"10.1117/12.2679729","DOIUrl":"https://doi.org/10.1117/12.2679729","url":null,"abstract":"This study investigates the use of U-shaped cladded plastic optical fiber (POF) and glass optical fiber (GOF) probes for refractive index (RI) sensing as they allow a simple one-step fabrication process. The RI sensitivity of the U-shaped cladded POF probes were evaluated in narrow (1.333 to 1.348, increment of 0.003 RI) and intermediate RI ranges (1.34 to 1.39, increment of 0.01 RI). No considerable improvement or drop was observed. However, the U-shaped silica cladded GOF showed 1.3 and 1.54 -fold improvement in the RI sensitivity in comparison to the decladded probes in the narrow and intermediate RI range respectively. The highest sensitivities for cladded POF and GOF probes in the intermediate RI range were 4.7 and 10.8 ΔA530 nm/ΔRIU respectively.","PeriodicalId":424244,"journal":{"name":"European Workshop on Optical Fibre Sensors","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125450289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hongxiang Jia, Taylor Iantosca, Jonathan M. Wheeler, M. Digonnet
We report the best noise and drift ever achieved by a laser-driven FOG, namely an angular random walk of 368 μdeg/√h and a drift of 6.66 mdeg/h. This improvement was achieved by interrogating the 3-km Sagnac interferometer of the FOG with a low-coherence light source consisting of three lasers broadened by the same noise-driven phase modulator, which further reduces the temporal coherence compared to a single broadened laser. Proper optical gating is also applied to suppress the residual drift due to the Kerr effect. The experimental results agree well with our prediction that both the noise and the drift improve as the square root of the number of lasers. Using multiple lasers also improves the mean-wavelength stability of the light source compared to a single laser. Thanks to the low cost of semiconductor lasers, this technique is a promising and cost-effective solution that can be easily extended to a larger number of lasers for further reduction of the noise and drift in high-accuracy FOGs.
{"title":"Fiber optic gyroscope interrogated with three multiplexed broadened semiconductor lasers","authors":"Hongxiang Jia, Taylor Iantosca, Jonathan M. Wheeler, M. Digonnet","doi":"10.1117/12.2678384","DOIUrl":"https://doi.org/10.1117/12.2678384","url":null,"abstract":"We report the best noise and drift ever achieved by a laser-driven FOG, namely an angular random walk of 368 μdeg/√h and a drift of 6.66 mdeg/h. This improvement was achieved by interrogating the 3-km Sagnac interferometer of the FOG with a low-coherence light source consisting of three lasers broadened by the same noise-driven phase modulator, which further reduces the temporal coherence compared to a single broadened laser. Proper optical gating is also applied to suppress the residual drift due to the Kerr effect. The experimental results agree well with our prediction that both the noise and the drift improve as the square root of the number of lasers. Using multiple lasers also improves the mean-wavelength stability of the light source compared to a single laser. Thanks to the low cost of semiconductor lasers, this technique is a promising and cost-effective solution that can be easily extended to a larger number of lasers for further reduction of the noise and drift in high-accuracy FOGs.","PeriodicalId":424244,"journal":{"name":"European Workshop on Optical Fibre Sensors","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127821316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Pospori, A. Ioannou, J. Melo, P. Antunes, H. Varum, C. Marques, K. Kalli
A novel prototype sensing device based on polymer (CYTOP-XYLEX) optical fibre Bragg grating sensors was developed to monitor temperature and relative humidity levels of reinforced concrete from its initial curing phase to a prolonged period. The prototype can be used for concrete quality control offering numerous advantages, such as small size, robustness, high sensitivity, and low-cost continuous in-situ measurements.
{"title":"Concrete curing monitoring using polymer optical fibre Bragg grating sensors","authors":"A. Pospori, A. Ioannou, J. Melo, P. Antunes, H. Varum, C. Marques, K. Kalli","doi":"10.1117/12.2678107","DOIUrl":"https://doi.org/10.1117/12.2678107","url":null,"abstract":"A novel prototype sensing device based on polymer (CYTOP-XYLEX) optical fibre Bragg grating sensors was developed to monitor temperature and relative humidity levels of reinforced concrete from its initial curing phase to a prolonged period. The prototype can be used for concrete quality control offering numerous advantages, such as small size, robustness, high sensitivity, and low-cost continuous in-situ measurements.","PeriodicalId":424244,"journal":{"name":"European Workshop on Optical Fibre Sensors","volume":"137 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127475508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Lerner, T. Blanchet, R. Cotillard, M. Sosa, N. Roussel, G. Bouwmans, G. Laffont
We investigate the behavior and stability of fiber Bragg gratings written by femtosecond laser pulses in Ge-doped fused silica optical fibers, using both the phase mask and point-by-point techniques, during their annealing at 1200°C for 30 min and subsequent aging at 1000°C during 43 hours. Bragg wavelength drifts and reflected peak amplitude variations were shown to drastically differ depending on the writing scheme and thermal history. Particularly, we show that amplitude decay of point-by-point gratings at 1200°C may be easily mitigated by tuning the writing pulse energy. Future work may be pursued in order to finely unravel the high temperature mechanisms regarding the stability of fs-written fiber Bragg gratings used as temperature sensors in order to improve measurement stability and accuracy.
{"title":"High temperature annealing behavior of femtosecond written FBGs in Ge-doped fused silica optical fibers","authors":"A. Lerner, T. Blanchet, R. Cotillard, M. Sosa, N. Roussel, G. Bouwmans, G. Laffont","doi":"10.1117/12.2678399","DOIUrl":"https://doi.org/10.1117/12.2678399","url":null,"abstract":"We investigate the behavior and stability of fiber Bragg gratings written by femtosecond laser pulses in Ge-doped fused silica optical fibers, using both the phase mask and point-by-point techniques, during their annealing at 1200°C for 30 min and subsequent aging at 1000°C during 43 hours. Bragg wavelength drifts and reflected peak amplitude variations were shown to drastically differ depending on the writing scheme and thermal history. Particularly, we show that amplitude decay of point-by-point gratings at 1200°C may be easily mitigated by tuning the writing pulse energy. Future work may be pursued in order to finely unravel the high temperature mechanisms regarding the stability of fs-written fiber Bragg gratings used as temperature sensors in order to improve measurement stability and accuracy.","PeriodicalId":424244,"journal":{"name":"European Workshop on Optical Fibre Sensors","volume":"12643 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129122725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Faralli, T. Nannipieri, A. Signorini, F. Di Pasquale
We present a novel amplified space-time coding technique which combines cyclic-Simplex and Simplex binary codes to overcome the main limitations of conventional coding for OTDR based ultra-long distance distributed temperature sensing applications. The decoding process is performed in two successive steps, addressing the main issue related to the computational complexity of conventional codes, which increases quadratically with the code lenght, seriously affecting their performance when dealing with extremely long code-words. A link control technique is also proposed to suppress gain transients induced by the EDFA dynamics, avoiding performance degradation due to nonlinear effects and codewords distortion. The proposed scheme provides significant coding gain enhancement and stable operations below the stimulated Raman scattering threshold, pushing the performance of Raman based distributed temperature sensors close to their physical limit using commercial off-the-shelf components.
{"title":"Amplified space-time coding for ultra-long-distance Raman distributed temperature sensing","authors":"S. Faralli, T. Nannipieri, A. Signorini, F. Di Pasquale","doi":"10.1117/12.2678086","DOIUrl":"https://doi.org/10.1117/12.2678086","url":null,"abstract":"We present a novel amplified space-time coding technique which combines cyclic-Simplex and Simplex binary codes to overcome the main limitations of conventional coding for OTDR based ultra-long distance distributed temperature sensing applications. The decoding process is performed in two successive steps, addressing the main issue related to the computational complexity of conventional codes, which increases quadratically with the code lenght, seriously affecting their performance when dealing with extremely long code-words. A link control technique is also proposed to suppress gain transients induced by the EDFA dynamics, avoiding performance degradation due to nonlinear effects and codewords distortion. The proposed scheme provides significant coding gain enhancement and stable operations below the stimulated Raman scattering threshold, pushing the performance of Raman based distributed temperature sensors close to their physical limit using commercial off-the-shelf components.","PeriodicalId":424244,"journal":{"name":"European Workshop on Optical Fibre Sensors","volume":"137 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133898212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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