This paper outlines improvements that have been made in a multiaxis fiber grating strain sensor that can also be used in certain cases to measure temperature. The current status and future prospects for these senors are outlined.
{"title":"Advanced fiber optic sensors capable of multiparameter sensing","authors":"E. Udd, W. Schulz, J. Seim","doi":"10.1117/12.323433","DOIUrl":"https://doi.org/10.1117/12.323433","url":null,"abstract":"This paper outlines improvements that have been made in a multiaxis fiber grating strain sensor that can also be used in certain cases to measure temperature. The current status and future prospects for these senors are outlined.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132012772","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}
Fiber Bragg grating sensors generally consist of a single grating written in a low-birefringent optical fiber. The wavelength shift of the peak in the reflected spectrum from these sensors can be used to measure a single component of strain or a change in temperature [Lawrence, 1997]. Fibers are also available with a significant enough birefringence to maintain the polarization state along great lengths and through many turns. This 'polarization maintaining' fiber is commercially available through several companies and in several configurations (including different cladding material and wavelength shift). The grating usually extends approximately 3 mm - 5 m in length. Udd gives a detailed explanation of fiber optics, Bragg gratings and birefringence [Udd, 1991]. As light from an LED is passed through the fiber, only the wavelength consistent with the grating period will be reflected back towards the source. All other wavelengths will pass through. The reflected spectrum will shift as the fiber is strained along its axis at the grating location. Strain or temperature changes at any other location have negligible effect on the wavelength encoded data output. When the Fiber Bragg grating single-axis sensor (termed fiber hereafter) is strained transversely the wavelength will separate into two distinct peaks according to a mathematical relationship defined by Lawrence and Nelson [Lawrence, Nelson et al. 96]. Using these Fiber Bragg grating fibers a corrosion sensor which measures the rate of material was developed. The principle behind this newly developed corrosion sensor is to pre-stress the fiber with a known load. The load is applied by inducing a uniform hoop stress through pressure fitted cylinders around the fiber. This induced stress creates a broadening of the reflected spectrum until the bifurcation of the reflected intensity peaks is distinguishable. As the material from the outer cylinder corrodes away the applied stress will be relieved. Finally, when no load is achieved, the reflected spectrum will have a single peak centered around the nominal Bragg grating wavelength. If a polarizing-maintaining 3-axis grating is used then the sensor would be even more sensitive, having two distinct peaks in each wavelength regime which shift.
{"title":"Material removal rate fiber optic corrosion sensor","authors":"A. Trego, E. Haugse, E. Udd","doi":"10.1117/12.323422","DOIUrl":"https://doi.org/10.1117/12.323422","url":null,"abstract":"Fiber Bragg grating sensors generally consist of a single grating written in a low-birefringent optical fiber. The wavelength shift of the peak in the reflected spectrum from these sensors can be used to measure a single component of strain or a change in temperature [Lawrence, 1997]. Fibers are also available with a significant enough birefringence to maintain the polarization state along great lengths and through many turns. This 'polarization maintaining' fiber is commercially available through several companies and in several configurations (including different cladding material and wavelength shift). The grating usually extends approximately 3 mm - 5 m in length. Udd gives a detailed explanation of fiber optics, Bragg gratings and birefringence [Udd, 1991]. As light from an LED is passed through the fiber, only the wavelength consistent with the grating period will be reflected back towards the source. All other wavelengths will pass through. The reflected spectrum will shift as the fiber is strained along its axis at the grating location. Strain or temperature changes at any other location have negligible effect on the wavelength encoded data output. When the Fiber Bragg grating single-axis sensor (termed fiber hereafter) is strained transversely the wavelength will separate into two distinct peaks according to a mathematical relationship defined by Lawrence and Nelson [Lawrence, Nelson et al. 96]. Using these Fiber Bragg grating fibers a corrosion sensor which measures the rate of material was developed. The principle behind this newly developed corrosion sensor is to pre-stress the fiber with a known load. The load is applied by inducing a uniform hoop stress through pressure fitted cylinders around the fiber. This induced stress creates a broadening of the reflected spectrum until the bifurcation of the reflected intensity peaks is distinguishable. As the material from the outer cylinder corrodes away the applied stress will be relieved. Finally, when no load is achieved, the reflected spectrum will have a single peak centered around the nominal Bragg grating wavelength. If a polarizing-maintaining 3-axis grating is used then the sensor would be even more sensitive, having two distinct peaks in each wavelength regime which shift.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131581210","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}
We propose an alternative configuration for an interferometric distributed fiber optic sensor. The sensor uses a combination of Mach-Zehnder and Sagnac interferometers that share the same fiber. The output of the Sagnac interferometer is proportional to the product of the position where the disturbance was applied and the magnitude of the disturbance. The output of the Mach-Zehnder interferometer is a function of the disturbance magnitude only. The position and magnitude of a disturbance applied to the sensing fiber can thus be obtained from these two signals. Results obtained with a 200 m distributed fiber sensor are discussed.
{"title":"Modified Sagnac/Mach-Zehnder interferometer for distributed disturbance sensing","authors":"A. Chtcherbakov, P. Swart, S. Spammer, B. Lacquet","doi":"10.1117/12.323432","DOIUrl":"https://doi.org/10.1117/12.323432","url":null,"abstract":"We propose an alternative configuration for an interferometric distributed fiber optic sensor. The sensor uses a combination of Mach-Zehnder and Sagnac interferometers that share the same fiber. The output of the Sagnac interferometer is proportional to the product of the position where the disturbance was applied and the magnitude of the disturbance. The output of the Mach-Zehnder interferometer is a function of the disturbance magnitude only. The position and magnitude of a disturbance applied to the sensing fiber can thus be obtained from these two signals. Results obtained with a 200 m distributed fiber sensor are discussed.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121787991","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 novel low cost interferometric displacement sensor has been developed which tracks distance from the tip of a fiber optic probe. A unique interrogation technique is used which produces a 32-bit phase word, giving the system a dynamic range greater than 109. Therefore, a displacement resolution of less than 0.01 nm can be achieved with a full range of 6 mm. The measurement range can be extended beyond 10 m by simply adjusting the digital fringe counter and sacrificing resolution yet maintaining the greater than 109 dynamic range. Demodulation rates of 40 kHz have been achieved which facilitates dynamic measurements. Results from an application to hard disk (HD) profilometry are presented.
{"title":"Fiber optic displacement sensor","authors":"P. Davis, J. Bush, G. Maurer","doi":"10.1117/12.323427","DOIUrl":"https://doi.org/10.1117/12.323427","url":null,"abstract":"A novel low cost interferometric displacement sensor has been developed which tracks distance from the tip of a fiber optic probe. A unique interrogation technique is used which produces a 32-bit phase word, giving the system a dynamic range greater than 109. Therefore, a displacement resolution of less than 0.01 nm can be achieved with a full range of 6 mm. The measurement range can be extended beyond 10 m by simply adjusting the digital fringe counter and sacrificing resolution yet maintaining the greater than 109 dynamic range. Demodulation rates of 40 kHz have been achieved which facilitates dynamic measurements. Results from an application to hard disk (HD) profilometry are presented.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"573 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117200910","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 twin-bridge fiber optic calorimeter has been built and is currently being tested at Los Alamos National Laboratory (LANL). The intrinsic optical phase shift induced by changes in temperature is measured in both a reference canister and a sample canister. This system incorporates two Michelson interferometers each with an optical path mismatch of 1.6 km. A digital demodulation scheme is used which produces a 32 bit phase word which tracks up to 500,000 fringes with a resolution of 10-4 fringe, giving the system a dynamic range greater than 109. Both interferometers are demodulated simultaneously at a rate of 83 kHz. The phase difference between the reference and sample interferometers is proportional to the temperature difference between the canisters and therefore correlates to the power produced by the sample in question. The optical system performance will be described along with preliminary calorimetric measurement results.
{"title":"Fiber optic calorimeter","authors":"P. Davis, J. Bush, S. Bayliss, C. Rudy","doi":"10.1117/12.323428","DOIUrl":"https://doi.org/10.1117/12.323428","url":null,"abstract":"A twin-bridge fiber optic calorimeter has been built and is currently being tested at Los Alamos National Laboratory (LANL). The intrinsic optical phase shift induced by changes in temperature is measured in both a reference canister and a sample canister. This system incorporates two Michelson interferometers each with an optical path mismatch of 1.6 km. A digital demodulation scheme is used which produces a 32 bit phase word which tracks up to 500,000 fringes with a resolution of 10-4 fringe, giving the system a dynamic range greater than 109. Both interferometers are demodulated simultaneously at a rate of 83 kHz. The phase difference between the reference and sample interferometers is proportional to the temperature difference between the canisters and therefore correlates to the power produced by the sample in question. The optical system performance will be described along with preliminary calorimetric measurement results.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"56 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114776961","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}
This paper provides a broad overview of the field of fiber optic chemical sensors. Several different types of fiber optic sensors and probes are described, and references are cited for each category discussed.
{"title":"Fiber optic chemical sensors","authors":"C. Jung, D. Mccrae, E. Saaski","doi":"10.1117/12.323416","DOIUrl":"https://doi.org/10.1117/12.323416","url":null,"abstract":"This paper provides a broad overview of the field of fiber optic chemical sensors. Several different types of fiber optic sensors and probes are described, and references are cited for each category discussed.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128299735","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}
Integrated-optic devices for use in high-voltage substations are reviewed. Specifically, two types of integrated-optic Mach-Zehnder and the integrated-optic Pockels cell are described and compared. A system for monitoring the condition of fluid-and-paper insulation systems, such as are used in many current transformers and power transformer bushings, is also described. This condition monitoring system measures the dissipation factor of an insulation system being monitored. It uses an integrated-optic Pockels cell to measure the phase of the voltage on the high-voltage transmission line to which the insulation system is connected. Preliminary results, showing that the system is capable of measuring the dissipation factor to an accuracy of 0.5%, are presented.
{"title":"Integrated-optic sensors for high-voltage substation applications","authors":"N. Jaeger","doi":"10.1117/12.323430","DOIUrl":"https://doi.org/10.1117/12.323430","url":null,"abstract":"Integrated-optic devices for use in high-voltage substations are reviewed. Specifically, two types of integrated-optic Mach-Zehnder and the integrated-optic Pockels cell are described and compared. A system for monitoring the condition of fluid-and-paper insulation systems, such as are used in many current transformers and power transformer bushings, is also described. This condition monitoring system measures the dissipation factor of an insulation system being monitored. It uses an integrated-optic Pockels cell to measure the phase of the voltage on the high-voltage transmission line to which the insulation system is connected. Preliminary results, showing that the system is capable of measuring the dissipation factor to an accuracy of 0.5%, are presented.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116390212","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}
Pacific Northwest National Laboratory is developing a fiber optic grating sensor demodulator using a low cost static Fourier-transform interferometer. The spectrometer uses a fiber optic source and a plane mirror to form an interferogram in the spatial domain that is recorded by a linear photodiode array detector. Using this instrument with an interferogram fringe spacing of 20 microns provides fiber grating strain resolution of about 700-microstrain.
{"title":"Fiber optic grating demodulation using a Fourier-transform spectrometer","authors":"N. Anheier, M. Bliss, R. A. Craig","doi":"10.1117/12.323419","DOIUrl":"https://doi.org/10.1117/12.323419","url":null,"abstract":"Pacific Northwest National Laboratory is developing a fiber optic grating sensor demodulator using a low cost static Fourier-transform interferometer. The spectrometer uses a fiber optic source and a plane mirror to form an interferogram in the spatial domain that is recorded by a linear photodiode array detector. Using this instrument with an interferogram fringe spacing of 20 microns provides fiber grating strain resolution of about 700-microstrain.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123339122","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}
This paper outlines recent progress made by Optiphase Inc.in the development of low-cost, high performance interferometric demodulators applied to multi-channel interrogation. The paper's focus is on the Optiphase digital demodulation concept applied first for single channel operation and then to multi-channel operation. This paper also presents single and multi-channel demodulation test data taken from hardware developed for these applications.
{"title":"Multichannel interferometric demodulator","authors":"J. Bush, A. Cekorich, C. Kirkendall","doi":"10.1117/12.285601","DOIUrl":"https://doi.org/10.1117/12.285601","url":null,"abstract":"This paper outlines recent progress made by Optiphase Inc.in the development of low-cost, high performance interferometric demodulators applied to multi-channel interrogation. The paper's focus is on the Optiphase digital demodulation concept applied first for single channel operation and then to multi-channel operation. This paper also presents single and multi-channel demodulation test data taken from hardware developed for these applications.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125385963","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}
This paper overviews recent progress made on the development of a 3 axis fiber optic strain sensor that has the potential to measure temperature as well. Initial efforts have been conducted to demonstrate the performance potential of an approach using dual overlaid fiber gratings written at 1300 and 1550 nm written onto conventional polarization maintaining fiber. This paper reports on some of the results of this study and indicates the direction of future efforts to develop a multiplexable, single point three axis strain and temperature fiber grating sensor.
{"title":"Progress on developing a multiaxis fiber optic strain sensor","authors":"E. Udd, C. M. Lawrence, D. Nelson","doi":"10.1117/12.285604","DOIUrl":"https://doi.org/10.1117/12.285604","url":null,"abstract":"This paper overviews recent progress made on the development of a 3 axis fiber optic strain sensor that has the potential to measure temperature as well. Initial efforts have been conducted to demonstrate the performance potential of an approach using dual overlaid fiber gratings written at 1300 and 1550 nm written onto conventional polarization maintaining fiber. This paper reports on some of the results of this study and indicates the direction of future efforts to develop a multiplexable, single point three axis strain and temperature fiber grating sensor.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"310 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115864122","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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