Strains produced in the core of a multi-parameter Bragg grating sensor by transverse loading, axial loading or a uniform temperature change are computed by finite element analyses. The sensor is formed by writing gratings at two wavelengths in polarization maintaining fiber in which birefringence in the core is induced by an elliptical stress applying region. The finite element model accounts for the differences in geometry and mechanical properties of the different regions of the fiber. The computed strains are needed to determine the elements of a matrix that relates wavelength shifts of Bragg peaks to axial strain, two components of transverse strain and temperature change.
{"title":"Modeling of the multiparameter Bragg grating sensor","authors":"C. M. Lawrence, D. Nelson, A. Makino, E. Udd","doi":"10.1117/12.285603","DOIUrl":"https://doi.org/10.1117/12.285603","url":null,"abstract":"Strains produced in the core of a multi-parameter Bragg grating sensor by transverse loading, axial loading or a uniform temperature change are computed by finite element analyses. The sensor is formed by writing gratings at two wavelengths in polarization maintaining fiber in which birefringence in the core is induced by an elliptical stress applying region. The finite element model accounts for the differences in geometry and mechanical properties of the different regions of the fiber. The computed strains are needed to determine the elements of a matrix that relates wavelength shifts of Bragg peaks to axial strain, two components of transverse strain and temperature change.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"22 15","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113971316","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}
Speckle based fiber optic sensors have been developed and used in laboratory and field settings for a number of years. In the case of speckle-based fiber optic vibration sensor, optical signal processing of the field emerging form a multimode fiber has been performed through the use of intensity modulating masks. In such cases, portions of the speckle pattern are not allowed to illuminate a photodetector thereby performing forms of statistical selection of modal patterns. While this technique is robust, it does inherently reduce the sensor's operational dynamic range, and signal-to-noise ratio, due to the simple fact that a portion of the light field is not used. By contrast, it is possible to use phase-contrast enhancing techniques found in microscopy to phase-modulate the fiber's speckle pattern. The performance of a multimode fiber optic sensor using these techniques is compared with the more traditional intensity-modulating fiber optic sensor.
{"title":"Phase-contrast enhancements to a speckle-based fiber optic sensor","authors":"P. Fuhr","doi":"10.1117/12.285599","DOIUrl":"https://doi.org/10.1117/12.285599","url":null,"abstract":"Speckle based fiber optic sensors have been developed and used in laboratory and field settings for a number of years. In the case of speckle-based fiber optic vibration sensor, optical signal processing of the field emerging form a multimode fiber has been performed through the use of intensity modulating masks. In such cases, portions of the speckle pattern are not allowed to illuminate a photodetector thereby performing forms of statistical selection of modal patterns. While this technique is robust, it does inherently reduce the sensor's operational dynamic range, and signal-to-noise ratio, due to the simple fact that a portion of the light field is not used. By contrast, it is possible to use phase-contrast enhancing techniques found in microscopy to phase-modulate the fiber's speckle pattern. The performance of a multimode fiber optic sensor using these techniques is compared with the more traditional intensity-modulating fiber optic sensor.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"62 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":"122167004","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 optic surface plasmon resonance sensor is described. Experimental results are presented which demonstrate a resolution of approximately 8 by 10-5 refractive index units for this system. The detection of heavy metal Cu and Pb ions in solutionis demonstrated using the SPR sensor as the working electrode in an anodic stripping voltammetry experiment.
{"title":"Surface plasmon resonance fiber optic sensors","authors":"C. Jung","doi":"10.1117/12.285592","DOIUrl":"https://doi.org/10.1117/12.285592","url":null,"abstract":"A fiber optic surface plasmon resonance sensor is described. Experimental results are presented which demonstrate a resolution of approximately 8 by 10-5 refractive index units for this system. The detection of heavy metal Cu and Pb ions in solutionis demonstrated using the SPR sensor as the working electrode in an anodic stripping voltammetry experiment.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"34 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":"125714503","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 development of a rugged optical fiber telemetry system for coiled-tubing earth-drilling is described. The transmitter and receiver of the telemetry system are located on the surface. A high temperature fiber cable connects a serial array of downhole modulators with the surface. Each modulator consists of an intrinsic fiber Bragg grating (FBG) fixed to a piezoelectric transducer (PZ). Each modulating signal causes a PZ to stretch its attached FBG, shifting the wavelength of the light reflected by the grating. The wavelength shift of the grating-reflected light is detected at the output using a Mach-Zehnder interferometer.
{"title":"Rugged telemetry system for coiled-tubing earth drilling","authors":"R. Weis, B. M. Beadle","doi":"10.1117/12.285607","DOIUrl":"https://doi.org/10.1117/12.285607","url":null,"abstract":"The development of a rugged optical fiber telemetry system for coiled-tubing earth-drilling is described. The transmitter and receiver of the telemetry system are located on the surface. A high temperature fiber cable connects a serial array of downhole modulators with the surface. Each modulator consists of an intrinsic fiber Bragg grating (FBG) fixed to a piezoelectric transducer (PZ). Each modulating signal causes a PZ to stretch its attached FBG, shifting the wavelength of the light reflected by the grating. The wavelength shift of the grating-reflected light is detected at the output using a Mach-Zehnder interferometer.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"5 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132331476","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}
E. Udd, Kelli Corona-Bittick, J. Dorr, K. Slattery
A simple, potentially low cost fiber grating demodulation is described that can be used to measure very fast strain events. The unit consists of a broadband light emitting diode light source that is used to illuminate a fiber grating. The narrow band reflected light signal is directed toward a broadband chirped fiber grating whose transmission and reflection is monitored by a pair of receivers. The ratioed output can be used to monitor fast events. An example of using this sensor to support impact testing is given.
{"title":"Low-cost fiber grating sensor demodulator using a temperature-compensated fiber grating spectral filter","authors":"E. Udd, Kelli Corona-Bittick, J. Dorr, K. Slattery","doi":"10.1117/12.285606","DOIUrl":"https://doi.org/10.1117/12.285606","url":null,"abstract":"A simple, potentially low cost fiber grating demodulation is described that can be used to measure very fast strain events. The unit consists of a broadband light emitting diode light source that is used to illuminate a fiber grating. The narrow band reflected light signal is directed toward a broadband chirped fiber grating whose transmission and reflection is monitored by a pair of receivers. The ratioed output can be used to monitor fast events. An example of using this sensor to support impact testing is given.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"3180 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":"131238360","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}
While fiber optic Bragg gratings sensors have emerged as a viable commercial product they possess the inherent inflexibility that once written, the nonstressed gratin spacing is fixed. We have begun to explore an alternative method of fabricating Bragg sensors - one where you have a single fiber optic Bragg grating sensor, but where you are able to write your own grating prior to parameter measuring with the broadband light source. In this alternative, a photosensitive fiber core material exists at the FBGS sensing 'site' along the fiber. THe diffraction grating is written via a deliberate intensity variation in the light which is injected into the fiber. The slight difference in refractive index between the photogrey section of the core and the 'regular' fiber causes an internal Fabry-Perot resonator cavity to be established. The intensity-modulated high power laser bit stream reflects back and forth within this cavity establishing a standing wave pattern. This pattern may be varied, and hence the grating spacing is variable, by changing the high power laser's bit pattern. This standing wave pattern effectively illuminates the photogrey section nonuniformly with the high power portions of the standing wave pattern causing more darkening - thereby in essence creating the Bragg diffraction grating.
{"title":"Re-writable fiber optic Bragg gratings for multiple parameter sensing","authors":"P. Fuhr, E. Udd","doi":"10.1117/12.285595","DOIUrl":"https://doi.org/10.1117/12.285595","url":null,"abstract":"While fiber optic Bragg gratings sensors have emerged as a viable commercial product they possess the inherent inflexibility that once written, the nonstressed gratin spacing is fixed. We have begun to explore an alternative method of fabricating Bragg sensors - one where you have a single fiber optic Bragg grating sensor, but where you are able to write your own grating prior to parameter measuring with the broadband light source. In this alternative, a photosensitive fiber core material exists at the FBGS sensing 'site' along the fiber. THe diffraction grating is written via a deliberate intensity variation in the light which is injected into the fiber. The slight difference in refractive index between the photogrey section of the core and the 'regular' fiber causes an internal Fabry-Perot resonator cavity to be established. The intensity-modulated high power laser bit stream reflects back and forth within this cavity establishing a standing wave pattern. This pattern may be varied, and hence the grating spacing is variable, by changing the high power laser's bit pattern. This standing wave pattern effectively illuminates the photogrey section nonuniformly with the high power portions of the standing wave pattern causing more darkening - thereby in essence creating the Bragg diffraction grating.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"50 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":"123265329","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. Kenny, E. Gutierrez, A. Lucia, M. Whelan, F. Gaiazzi
We present recent work on fiber optic sensor systems for structural element characterization and monitoring. One particular application area currently under study is the characterization and testing of pultruded composite beams. The motivation behind this project and current status is described. Fiber optic sensor systems to suit the application have been developed. In particular, the development of both AO tunable filter and all-fiber passive demodulation schemes for in-fiber Bragg grating sensors is described.
{"title":"Fiber optic sensors for characterization of composite structural materials and structural monitoring","authors":"R. Kenny, E. Gutierrez, A. Lucia, M. Whelan, F. Gaiazzi","doi":"10.1117/12.285597","DOIUrl":"https://doi.org/10.1117/12.285597","url":null,"abstract":"We present recent work on fiber optic sensor systems for structural element characterization and monitoring. One particular application area currently under study is the characterization and testing of pultruded composite beams. The motivation behind this project and current status is described. Fiber optic sensor systems to suit the application have been developed. In particular, the development of both AO tunable filter and all-fiber passive demodulation schemes for in-fiber Bragg grating sensors is described.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"50 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":"128661912","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}
Current sensors for monitoring web manufacturing processes generally provide only point measurements with the result that a very small area of the web is actually characterized. This paper describes a new web sensing concept based upon the use of a distributed fiber optic detector.
{"title":"Distributed fiber optic sensors for web measurement","authors":"J. Griffin, P. Reeder, S. Poulson","doi":"10.1117/12.285594","DOIUrl":"https://doi.org/10.1117/12.285594","url":null,"abstract":"Current sensors for monitoring web manufacturing processes generally provide only point measurements with the result that a very small area of the web is actually characterized. This paper describes a new web sensing concept based upon the use of a distributed fiber optic detector.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"40 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":"124038694","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}
Researchers throughout the world have successfully developed embedded long-lived silica-based fiber optic sensors for the performance and health monitoring of reinforced concrete structures. We have examined the user of polymer optical fiber (POF) as the base material for fiber optic sensors which are to be embedded into concrete structures. Such POF sensors hold the possibility for considerably reduced expense both in terms of actual component costs and, perhaps more importantly, in the relative ease with which such sensor may be embedded into concrete structures. Results of our laboratory and field studies, where POF sensors were embedded into an in-service railroad bridge, are discussed.
{"title":"Polymer optical fiber sensing of concrete structures","authors":"P. Fuhr, D. Huston","doi":"10.1117/12.285598","DOIUrl":"https://doi.org/10.1117/12.285598","url":null,"abstract":"Researchers throughout the world have successfully developed embedded long-lived silica-based fiber optic sensors for the performance and health monitoring of reinforced concrete structures. We have examined the user of polymer optical fiber (POF) as the base material for fiber optic sensors which are to be embedded into concrete structures. Such POF sensors hold the possibility for considerably reduced expense both in terms of actual component costs and, perhaps more importantly, in the relative ease with which such sensor may be embedded into concrete structures. Results of our laboratory and field studies, where POF sensors were embedded into an in-service railroad bridge, are discussed.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"93 7 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":"128938969","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}
An Erbium amplified spontaneous emission (ASE) source is described and test results are presented. The ASE output power, spectrum, coherence, relative intensity noise (RIN), and polarization were measured for three different Erbium doped fibers of various lengths. Output powers up to 15 mW were achieved with 70 mW of 980 nm pump power. Measurement of the ASE coherence resulted in 0.5 mm at the -30 dB level while the RIN was measured to be < -125 dB/rt- Hz. The coherence and noise characteristics of this source match specifications for a low noise fiber optic gyroscope and since the source design is simple, a low cost Erbium ASE source can be built.
{"title":"Broadband erbium source for fiber optic sensor applications","authors":"P. Davis, J. Bush","doi":"10.1117/12.285600","DOIUrl":"https://doi.org/10.1117/12.285600","url":null,"abstract":"An Erbium amplified spontaneous emission (ASE) source is described and test results are presented. The ASE output power, spectrum, coherence, relative intensity noise (RIN), and polarization were measured for three different Erbium doped fibers of various lengths. Output powers up to 15 mW were achieved with 70 mW of 980 nm pump power. Measurement of the ASE coherence resulted in 0.5 mm at the -30 dB level while the RIN was measured to be < -125 dB/rt- Hz. The coherence and noise characteristics of this source match specifications for a low noise fiber optic gyroscope and since the source design is simple, a low cost Erbium ASE source can be built.","PeriodicalId":293004,"journal":{"name":"Pacific Northwest Fiber Optic Sensor","volume":"1 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":"129889992","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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