This paper presents an optical fibre pressure and temperature sensor (OFPTS) system, which is adapted for use as a urodynamic pressure measurement system (UPS) for differential pressure measurement with temperature compensation. The OFTPS is based on a Fabry Perot interferometer (FPI), which acts as a pressure sensor and includes an embedded fibre Bragg grating (FBG) for temperature measurement. The sensor system is evaluated in a lower urinary tract (LUT) simulator, which simulates the bladder, rectum and detrusor muscle. The system was benchmarked against a commercially available urodynamic system, at the University Hospital Limerick (UHL) Urology Clinic. Both systems demonstrate a high correlation with a relative pressure variation of less than ±2.8cmH2O for abdominal and ±4cmH2O for vesical pressure. The repetitive measurement of the OFPTS system in the LUT simulator against the commercial system demonstrated the high repeatability. Furthermore, the low fabrication cost makes the OFPTS a potentially interesting instrument for urodynamic and other medical applications.
In this paper a novel patent pending high resolution optical fibre temperature sensor, based on an optical fibre pressure and temperature sensor (OFTPS), which is surrounded by an oil filled chamber, is presented. The OFPTS is based on a Fabry Perot interferometer (FPI) which has an embedded fibre Bragg grating (FBG). The high ratio between the volume of the oil filled outer cavity and the FPIs air filled cavity, results in a highly sensitive temperature sensor. The FBG element of the device can be used for wide range temperature measurements, and combining this capability with the high resolution capability of the FPI/oil cavity results in a wide range and high resolution temperature sensing device. The outer diameter of the sensor is less than 1mm in diameter and can be designed to be even smaller. The sensors temperature response was measured in a range of ΔT = 7K and resulted in a shift in the optical spectrum of ΔλF = 61.42nm. Therefore the Q-point of the reflected optical FPI spectrum is shifting with a sensitivity of sot = 8.77 nm/K . The sensitivity can easily be further increased by changing the oil/air volumetric ratio and therefore adapt the sensor to a wide variety of applications.
In this paper, two optical fibre sensors are presented: 1) based on extrinsic Fabry-Perot Interferometer (EFPI) with Fibre Bragg Grating array and 2) and EFPI sensor with a chirped Fibre Bragg grating (CFBG). The CFBG with EFPI sensor fabrication technique is described and temperature response of both sensors is presented. Such sensors have many potential applications including applications in the aerospace industry and medical industry (e.g. radio frequency thermal ablation of tumors).
A robust optical fibre based CO2 exhaust gas sensor operating in the mid infrared spectral range is described. It is
capable of detecting on board carbon dioxide (CO2) emissions from both diesel and petrol engines. The optical fibre
sensor is not cross sensitive to other gaseous species in the exhaust such as water vapour (H2O), carbon monoxide (CO),
oxides of nitrogen (NOx) or oxides of sulphur (SOx).The response of the sensor to carbon dioxide present in the exhaust
of Fiat Croma diesel engine are presented.
The development of an Ultra Violet (UV) Differential Optical Absorption Spectroscopy (DOAS) fibre-optic sensor for
the monitoring of nitric oxide gases is described in this paper. Experimental results describing the operation of this
sensor with cylinder gases are presented. These experimental results are compared with existing published spectroscopic
absorption measurements. The sensor was developed to operate within an exhaust environment and demonstrate a low
susceptibility to interferences from other gases present. A LabVIEW program was created to interrogate the highest
absorbing wavelength for nitric oxide and calculate the concentrations present before outputting them to the user. The
lower limit of detection for the sensor was found to be 5ppm with response times of 3.4 seconds.
A fibre-optic sensor for the monitoring of hazardous exhaust gases based on absorption in the ultra-violet region is
described. The loss of light through a gas cell across the UV/VIS spectrum was utilised to determine the level of
absorption for three of the exhaust gases present in an exhaust. The measured absorption specific to each of these test
gases Nitrogen Dioxide (NO2), Sulphur Dioxide (SO2) and Nitric Oxide (NO) was used in a variation of the Beer-Lambert law to determine the absorption line intensities for each of the gases. Theoretical absorption line intensities for
each of the exhaust gases compared favorably with our measured results. A LabVIEW program was created and utilised
to interrogate the highest absorbing wavelength for each of the gases and absorption recorded at these specific absorbing
wavelength were then input along with our measured absorption line intensities into the Beer-Lambert law to determine
the concentrations of each of the gases present in the test cell. In this manner the concentrations were calculated
immediately and then output to the user eliminating the need for processing the data after testing. A lower detection
level of 1ppm for both NO2 and SO2 and in the order of 26ppm for NO was achieved.
The reduction of harmful environmental pollutants which can have adverse effects on human health and the development of sensors capable of monitoring low concentrations of these pollutants is a major source of concern for many researchers today. This paper describes a multipass absorption cell used to detect and monitor the presence of several gases in the ultra violet and visible regions. An integrating sphere with a highly reflective internal coating (over 99%) was adapted in order to input and output various gases. Sulphur dioxide was detected in the ultra violet region, ozone in the visible and nitrogen dioxide in both the ultra violet and visible. This paper will report the generation of effective optical path lengths of up to 70 cm using a 5 cm diameter integrating sphere. This results in an optical sensor capable of detecting sulphur dioxide concentrations as low as 10 ppm, nitrogen dioxide concentrations as low as 4 ppm and ozone levels of the order of 500 ppm.
This paper describes two optical based sensors for the detection and quantification of vehicle exhaust pollutants. The first sensor consists of a single pass absorption cell. Broadband light from a deuterium/halogen source was transmitted through the cell from optical fibre and the resulting absorption is detected using a UV spectrometer which was also fibre coupled. The second approach includes an integrating sphere, which has been adapted for use as a multipass absorption cell. An ultraviolet LED was used as an emitter and a photodiode as the detector. Both were mounted directly on the sphere. The single pass absorption cell has been used to monitor nitric oxide, nitrogen dioxide and sulphur dioxide while the integrating sphere has been used to monitor nitrogen dioxide levels. Concentration levels of 10's of parts per million have been measured for each gas and sensor.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.