We experimentally investigate the applicability of the conventional near-field patter (NFP), far-field pattern (FFP) and variable aperture (VA) methods for measuring the effective mode-field diameter (MFD) of the higher-order mode which can be used for evaluating the splice loss accurately. We confirmed that the variation in measured MFD values obtained with FFP and VA methods can be converged by considering the minimum scanning angle and minimum numerical aperture (NA) respectively for both fundamental and higher-order modes. We reveal that the FFP and VA methods provide adequate effective MFD values in the FMF, which can be used for evaluating the splice loss based on the traditional Gaussian fitting model. We also found that the minimum NA in the VA method can be determined empirically as a function of the effective MFD.
{"title":"Effective mode-field diameter measurement for few-mode fibers","authors":"T. Matsui, T. Sakamoto, K. Nakajima","doi":"10.1117/12.2264979","DOIUrl":"https://doi.org/10.1117/12.2264979","url":null,"abstract":"We experimentally investigate the applicability of the conventional near-field patter (NFP), far-field pattern (FFP) and variable aperture (VA) methods for measuring the effective mode-field diameter (MFD) of the higher-order mode which can be used for evaluating the splice loss accurately. We confirmed that the variation in measured MFD values obtained with FFP and VA methods can be converged by considering the minimum scanning angle and minimum numerical aperture (NA) respectively for both fundamental and higher-order modes. We reveal that the FFP and VA methods provide adequate effective MFD values in the FMF, which can be used for evaluating the splice loss based on the traditional Gaussian fitting model. We also found that the minimum NA in the VA method can be determined empirically as a function of the effective MFD.","PeriodicalId":198716,"journal":{"name":"2017 25th Optical Fiber Sensors Conference (OFS)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130780695","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}
Ye Chen, M. Vidakovic, M. Fabian, M. Swift, L. Brun, T. Sun, K. Grattan
This paper presents the results obtained from fibre Bragg grating (FBG) sensors integrated into a railway current-collecting pantograph for accurate measurement of contact force and contact location when it is subjected to various temperature conditions. The temperature change of the pantograph is simulated, at the industrial laboratory of Brecknell Willis in the UK, by changing the DC current applied to pantograph from 0 to 1500 A. This test is primarily designed to verify the effectiveness of the temperature compensation mechanism built in the FBG sensor design. For this verification, 3 thermocouples co-located with the FBG sensor packages are used to measure the temperature change seen from 25 °C to 55 °C. The tests were repeated several times and the sensor system has shown its temperature-independence, confirming that the intrinsic cross-sensitivity of FBGs to temperature variation for strain measurement has been fully compensated through the use of this innovative sensor design and data processing.
{"title":"A temperature compensated fibre Bragg grating (FBG)-based sensor system for condition monitoring of electrified railway pantograph","authors":"Ye Chen, M. Vidakovic, M. Fabian, M. Swift, L. Brun, T. Sun, K. Grattan","doi":"10.1117/12.2263998","DOIUrl":"https://doi.org/10.1117/12.2263998","url":null,"abstract":"This paper presents the results obtained from fibre Bragg grating (FBG) sensors integrated into a railway current-collecting pantograph for accurate measurement of contact force and contact location when it is subjected to various temperature conditions. The temperature change of the pantograph is simulated, at the industrial laboratory of Brecknell Willis in the UK, by changing the DC current applied to pantograph from 0 to 1500 A. This test is primarily designed to verify the effectiveness of the temperature compensation mechanism built in the FBG sensor design. For this verification, 3 thermocouples co-located with the FBG sensor packages are used to measure the temperature change seen from 25 °C to 55 °C. The tests were repeated several times and the sensor system has shown its temperature-independence, confirming that the intrinsic cross-sensitivity of FBGs to temperature variation for strain measurement has been fully compensated through the use of this innovative sensor design and data processing.","PeriodicalId":198716,"journal":{"name":"2017 25th Optical Fiber Sensors Conference (OFS)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130926108","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}
The proposed technique consists in an optical fiber resonator interrogated for sensor characterization, implementing an alternative technique for dynamic range improvement. Such technique relies on the analysis of an added-signal caused by signal saturation, which occurs due to the broadening of the laser pulse. A wide study for different pulse widths is presented in this work, namely for 100 ns, 5 μs and 20 μs, being the last one related to the emergence of an added-signal for the proposed configuration. The behavior of the waveform in the presence of an intensity sensor is also characterized.
{"title":"Analysis of signal saturation in a fiber ring resonator integrating an intensity sensor","authors":"R. Magalhães, Susana O. Silva, O. Frazão","doi":"10.1117/12.2265877","DOIUrl":"https://doi.org/10.1117/12.2265877","url":null,"abstract":"The proposed technique consists in an optical fiber resonator interrogated for sensor characterization, implementing an alternative technique for dynamic range improvement. Such technique relies on the analysis of an added-signal caused by signal saturation, which occurs due to the broadening of the laser pulse. A wide study for different pulse widths is presented in this work, namely for 100 ns, 5 μs and 20 μs, being the last one related to the emergence of an added-signal for the proposed configuration. The behavior of the waveform in the presence of an intensity sensor is also characterized.","PeriodicalId":198716,"journal":{"name":"2017 25th Optical Fiber Sensors Conference (OFS)","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132305374","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}
M. Iuliano, D. Marini, F. Bastianini, G. Bolognini
In this paper we show a Brillouin optical time-domain analysis (BOTDA) sensing system experiment employing a tunable narrow-linewidth dual pump-probe source based on modified Brillouin ring laser technology. The developed cost-effective source generates a tunable pump-locked probe light, with suitable wavelength shift, large tuning range (∼200 MHz), narrow linewidth (<2.5 MHz) and adequate power (∼0.5 mW). The developed source was hence employed in BOTDA system experiments providing distributed sensing over ∼10 km single mode optical fiber, and attaining strain and temperature resolutions of ∼10με and ∼0.5 °C respectively, indicating the pump-probe source as an efficient and cost-effective solution for BOTDA avoiding high-frequency signal generators or complex locking techniques.
{"title":"BOTDA sensing system employing a tunable low-cost Brillouin fiber ring laser pump-probe source","authors":"M. Iuliano, D. Marini, F. Bastianini, G. Bolognini","doi":"10.1117/12.2267520","DOIUrl":"https://doi.org/10.1117/12.2267520","url":null,"abstract":"In this paper we show a Brillouin optical time-domain analysis (BOTDA) sensing system experiment employing a tunable narrow-linewidth dual pump-probe source based on modified Brillouin ring laser technology. The developed cost-effective source generates a tunable pump-locked probe light, with suitable wavelength shift, large tuning range (∼200 MHz), narrow linewidth (<2.5 MHz) and adequate power (∼0.5 mW). The developed source was hence employed in BOTDA system experiments providing distributed sensing over ∼10 km single mode optical fiber, and attaining strain and temperature resolutions of ∼10με and ∼0.5 °C respectively, indicating the pump-probe source as an efficient and cost-effective solution for BOTDA avoiding high-frequency signal generators or complex locking techniques.","PeriodicalId":198716,"journal":{"name":"2017 25th Optical Fiber Sensors Conference (OFS)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132732779","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}
Ji Su Kim, Sang-Pil Han, Kiwon Moon, H. Ryu, K. Park, M. Jeon
We present a terahertz (THz) radiation pumped by a passively mode-locked Yb-doped fiber laser using two fiber-pigtailed log-spiral-based low-temperature-grown (LTG) InGaAs photoconductive antenna (PCA) modules. The mode-locked fiber laser produces over 220 mW of the average optical power with positively chirped of 1.49 ps pulses. In order to generate THz radiation using the fiber-pigtailed PCA modules, the mode-locked optical pulses are pre-chirped with 538 fs using two diffraction gratings. We successfully achieved THz radiation over 2.0 THz using the pre-chirped pulses. We successfully observed the various absorption lines of water vapor dips in the free space of 120 mm.
{"title":"Terahertz radiation based on fiber-pigtailed InGaAs photoconductive antenna pumped by 1030 nm mode-locked Yb-doped fiber laser","authors":"Ji Su Kim, Sang-Pil Han, Kiwon Moon, H. Ryu, K. Park, M. Jeon","doi":"10.1117/12.2265379","DOIUrl":"https://doi.org/10.1117/12.2265379","url":null,"abstract":"We present a terahertz (THz) radiation pumped by a passively mode-locked Yb-doped fiber laser using two fiber-pigtailed log-spiral-based low-temperature-grown (LTG) InGaAs photoconductive antenna (PCA) modules. The mode-locked fiber laser produces over 220 mW of the average optical power with positively chirped of 1.49 ps pulses. In order to generate THz radiation using the fiber-pigtailed PCA modules, the mode-locked optical pulses are pre-chirped with 538 fs using two diffraction gratings. We successfully achieved THz radiation over 2.0 THz using the pre-chirped pulses. We successfully observed the various absorption lines of water vapor dips in the free space of 120 mm.","PeriodicalId":198716,"journal":{"name":"2017 25th Optical Fiber Sensors Conference (OFS)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128856826","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 fiber sensor based on cascaded eccentric-core fiber Bragg grating (ECFBG) and single mode fiber Bragg grating (SMFBG) is proposed and experimentally demonstrated to realize bending and axial strain measurement simultaneously. The ECFBG is sensitive to both bending and axial strain, and the SMFBG is insensitive to bend but sensitive to axial strain. The maximum bending sensitivities of the ECFBG are 36 pm/m−1 and −37 pm/m−1 at the bending direction of 0° and 180°, respectively. The strain sensitivities of the ECFBG and SMFBG are 0.76 pm/με and 0.72 pm/με, respectively.
{"title":"Simultaneous strain and directional bending sensor based on eccentric-core fiber Bragg grating","authors":"Jing Kong, Xiaowei Ouyang, Ai Zhou, Libo Yuan","doi":"10.1117/12.2264957","DOIUrl":"https://doi.org/10.1117/12.2264957","url":null,"abstract":"A fiber sensor based on cascaded eccentric-core fiber Bragg grating (ECFBG) and single mode fiber Bragg grating (SMFBG) is proposed and experimentally demonstrated to realize bending and axial strain measurement simultaneously. The ECFBG is sensitive to both bending and axial strain, and the SMFBG is insensitive to bend but sensitive to axial strain. The maximum bending sensitivities of the ECFBG are 36 pm/m<sup>−1</sup> and −37 pm/m<sup>−1</sup> at the bending direction of 0° and 180°, respectively. The strain sensitivities of the ECFBG and SMFBG are 0.76 pm/με and 0.72 pm/με, respectively.","PeriodicalId":198716,"journal":{"name":"2017 25th Optical Fiber Sensors Conference (OFS)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127805172","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}
Yurim Park, Hyunseok Kwon, P. Shrestha, Chun-Gon Kim
Composite materials provide many advantages over conventional materials including metals, especially for space applications. However, composites have failure modes that are complex and difficult to identify, and various cracks and delamination are predominantly difficult to detect visually. In this regard, an effective method of monitoring the integrity of composite materials and structures exposed to hazardous space environments is necessary to ensure the long-term reliability of composite materials in aerospace applications. FBG sensors are advantageous for space applications due to their immunity to various environments. In this study, FBG sensors were used to investigate LEO environment exposure monitoring of CFRP.
{"title":"Investigation of LEO environment exposure monitoring potential using embedded FBG sensors","authors":"Yurim Park, Hyunseok Kwon, P. Shrestha, Chun-Gon Kim","doi":"10.1117/12.2267564","DOIUrl":"https://doi.org/10.1117/12.2267564","url":null,"abstract":"Composite materials provide many advantages over conventional materials including metals, especially for space applications. However, composites have failure modes that are complex and difficult to identify, and various cracks and delamination are predominantly difficult to detect visually. In this regard, an effective method of monitoring the integrity of composite materials and structures exposed to hazardous space environments is necessary to ensure the long-term reliability of composite materials in aerospace applications. FBG sensors are advantageous for space applications due to their immunity to various environments. In this study, FBG sensors were used to investigate LEO environment exposure monitoring of CFRP.","PeriodicalId":198716,"journal":{"name":"2017 25th Optical Fiber Sensors Conference (OFS)","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127394308","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}
N. Ravichandran, R. E. Wijesinghe, Seung-Yeol Lee, M. F. Shirazi, Kibeom Park, H. Jung, Mansik Jeon, Jeehyun Kim
In this study, Optical coherence tomography (OCT) is demonstrated as a plausible optical tool for in vivo detection of plant seeds and its morphological changes during growth. The experiment was carried out on Capsicum annuum seeds that were treated with different molar concentrations of NaCl to investigate the most optimal concentration for the seed growth. The monitoring process was carried out for 9 consecutive days. The in vivo 2D OCT images of the treated seeds were obtained and compared with seeds that were grown with sterile distilled water. The obtained results confirm the feasibility of using OCT for the proposed application. Normalized A-scan analysis method is utilized for supporting the concluded results.
{"title":"Swept source optical coherence tomography for in vivo growth monitoring of Capsicum annuum seeds treated with different NaCl concentrations","authors":"N. Ravichandran, R. E. Wijesinghe, Seung-Yeol Lee, M. F. Shirazi, Kibeom Park, H. Jung, Mansik Jeon, Jeehyun Kim","doi":"10.1117/12.2267457","DOIUrl":"https://doi.org/10.1117/12.2267457","url":null,"abstract":"In this study, Optical coherence tomography (OCT) is demonstrated as a plausible optical tool for in vivo detection of plant seeds and its morphological changes during growth. The experiment was carried out on Capsicum annuum seeds that were treated with different molar concentrations of NaCl to investigate the most optimal concentration for the seed growth. The monitoring process was carried out for 9 consecutive days. The in vivo 2D OCT images of the treated seeds were obtained and compared with seeds that were grown with sterile distilled water. The obtained results confirm the feasibility of using OCT for the proposed application. Normalized A-scan analysis method is utilized for supporting the concluded results.","PeriodicalId":198716,"journal":{"name":"2017 25th Optical Fiber Sensors Conference (OFS)","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133750021","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}
Haritz Iribas, A. Loayssa, F. Sauser, M. Llera, S. Le Floch
We demonstrate a simple technique to enhance the signal-to-noise ratio (SNR) in Brillouin optical time-domain analysis sensors by the addition of gain and loss processes. The technique is based on the shift of the pump pulse optical frequency in a double-sideband probe system, so that the gain and loss processes take place at different frequencies. In this manner, the loss and the gain do not cancel each other out, and it makes possible to take advantage of both informations at the same time, obtaining an improvement of 3 dB on the SNR. Furthermore, the technique does not need an optical filtering, so that larger improvement on SNR and a simplification of the setup are obtained. The method is experimentally demonstrated in a 101 km fiber spool, obtaining a measurement uncertainty of 2.6 MHz (2σ) at the worst-contrast position for 2 m spatial resolution. This leads, to the best of our knowledge, to the highest figure-of-merit in a BOTDA without using coding or raman amplification.
{"title":"Enhancement of signal-to-noise ratio in Brillouin optical time domain analyzers by dual-probe detection","authors":"Haritz Iribas, A. Loayssa, F. Sauser, M. Llera, S. Le Floch","doi":"10.1117/12.2265054","DOIUrl":"https://doi.org/10.1117/12.2265054","url":null,"abstract":"We demonstrate a simple technique to enhance the signal-to-noise ratio (SNR) in Brillouin optical time-domain analysis sensors by the addition of gain and loss processes. The technique is based on the shift of the pump pulse optical frequency in a double-sideband probe system, so that the gain and loss processes take place at different frequencies. In this manner, the loss and the gain do not cancel each other out, and it makes possible to take advantage of both informations at the same time, obtaining an improvement of 3 dB on the SNR. Furthermore, the technique does not need an optical filtering, so that larger improvement on SNR and a simplification of the setup are obtained. The method is experimentally demonstrated in a 101 km fiber spool, obtaining a measurement uncertainty of 2.6 MHz (2σ) at the worst-contrast position for 2 m spatial resolution. This leads, to the best of our knowledge, to the highest figure-of-merit in a BOTDA without using coding or raman amplification.","PeriodicalId":198716,"journal":{"name":"2017 25th Optical Fiber Sensors Conference (OFS)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124248556","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}
K. Wysokiński, M. Filipowicz, T. Stanczyk, S. Lipinski, M. Napierala, M. Murawski, T. Nasilowski
CO2 optical fiber sensors based on polymer active materials are presented in this paper. Ethyl cellulose was proven to be a good candidate for a matrix material of the sensor, since it gives porous, thick and very sensitive layers. Low-cost sensors based on polymer optical fibers have been elaborated. Sensors have been examined for their sensitivity to CO2, temperature and humidity. Response time during cyclic exposures to CO2 have been also determined. Special layers exhibiting irreversible change of color during exposure to carbon dioxide have been developed. They have been verified for a possible use in smart food packaging.
{"title":"Active polymer materials for optical fiber CO2 sensors","authors":"K. Wysokiński, M. Filipowicz, T. Stanczyk, S. Lipinski, M. Napierala, M. Murawski, T. Nasilowski","doi":"10.1117/12.2265623","DOIUrl":"https://doi.org/10.1117/12.2265623","url":null,"abstract":"CO2 optical fiber sensors based on polymer active materials are presented in this paper. Ethyl cellulose was proven to be a good candidate for a matrix material of the sensor, since it gives porous, thick and very sensitive layers. Low-cost sensors based on polymer optical fibers have been elaborated. Sensors have been examined for their sensitivity to CO2, temperature and humidity. Response time during cyclic exposures to CO2 have been also determined. Special layers exhibiting irreversible change of color during exposure to carbon dioxide have been developed. They have been verified for a possible use in smart food packaging.","PeriodicalId":198716,"journal":{"name":"2017 25th Optical Fiber Sensors Conference (OFS)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124348676","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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