Our results suggest the value and applicability of intensity modulated fiber optic voltage sensors for measuring both steadystate waveforms and broadband transients which, coupled with the straightforward and compact design of the sensors. In this letter, we demonstrated an intensity modulated directional torsion sensor based on an inline machzehnder interferometer in singlemode fiber. Intensity modulated fiber optic sensor for health monitoring applications. Rf modulated fiber optic sensing systems and their applications g. Phase modulation sensors and interferometric sensors. Extrinsic fiber optic sensors use an optical fiber cable, normally a multimode one, to transmit modulated light from either a non fiber optical sensor, or an electronic sensor connected to an optical transmitter. Modeling and validation of performance limitations for the. Distributed pressure and temperature sensing based on. The sensing principle is that light intensity coupled to the sensor. The power responses of two wavelengths are measured by a dualchannel optical.
A highly sensitive intensitymodulated optical fiber. Introduction to fiber optic sensors and their types with applications in the year 1960, laser light was invented and after the invention of lasers, researchers had shown interest to study the applications of optical fiber communication systems for sensing, data communications, and many other applications. The intensity of the light wave traveling through an optical fiber can be modified by microbending of the optical fiber, by a change in coupling of the fiber with the. Typical configuration for a twowavelength intensity modulated optical fiber sensor system. This demonstrates that fiber optic sensors show high sensitivity and. Our results suggest the value and applicability of intensity modulated fiber optic voltage sensors for measuring both steadystate waveforms and broadband transients which, coupled with the straightforward and compact design of the sensors, should make them effective tools in electric grid monitoring. Fiber optic sensor technology miao yu assistant professor sensors and actuators laboratory department of mechanical engineering university of maryland, usa imac xxvi, orlando, fl feb 6, 2008. The sensor is constructed using single mode fiber smf and multimode fiber. Introduction to fiber optic sensors 7 intensity modulated fos phase modulated fos polarization modulated fos wavelength modulated fos phase modulated sensors usually use an. Intensitymodulated optical fiber sensors based on chirped. The highfrequency modulated optical signal serves as a carrier signal. Intensitymodulated magnetic field sensor based on fiber.
T ype of f iber o ptic s ensors fiber optic censors can be divided by. Some possible causes are scarce information, few research groups using them in a routine basis, and even fewer companies offering turnkey and affordable solutions. Fiber optic sensors have a set of properties that make them very attractive in biomechanics. Jan 15, 2020 our results suggest the value and applicability of intensity modulated fiber optic voltage sensors for measuring both steadystate waveforms and broadband transients which, coupled with the straightforward and compact design of the sensors, should make them effective tools in electric grid monitoring. Research article intensitymodulated fiber optic sensor for health monitoring applications. The intensity of the light wave traveling through an optical fiber. Losscompensation of intensity modulating fiberoptic sensors. In recent years, fiber optic sensors have been deployed successfully in the. A novel intensitymodulated optical fibre displacement sensor with convex reflector technology is described. Wang interference when two or more optical waves are present simultaneously in the same region of space, the total wave function is the. Pdf an intensitymodulated optical fibre displacement. Intensity modulated fiber optic sensors have the many distinct advantages associated with fiber optics that makes them suitable for several industrial and military applications. Optical fiber sensors intensity modulation sensors. Instead of using spectral analysis instruments, we present the novel intensity.
Theory and applications of coupling based intensity. Intensity modulated sensors light is required to exit the. Phase modulation sensors weichihwang department of power mechanical engineering. Intensity modulation an overview sciencedirect topics. Adamovsky national aeronautics and space administration, lewis research center cleveland, ohio 445 and j. Intensity modulated fibre optic sensors normally require only lowcost monitoring systems principally based on light emitting diodes and photo diodes. Fiberoptic sensors exploit the ability of waveguides to direct light with. Although, the accuracy of the sensor is far less that for interferometric sensors. Victor giurgiutiu, in structural health monitoring of aerospace composites, 2016. Handbook of optical sensors optical waveguide sensors. This classification can be arbitrary depending on how one frames the rules. Fundamentals and applications, fourth edition intensitymodulated sensors.
Threeaxis fiberoptic body force sensor for flexible. Although intensity modulated optical fiber sensors have been fabricated in many different designs and with varying. Introduction to fiber optic sensors and their types. Study of characterization of intensity modulated fiber. Fiber optic sensors have found applications in multiple industries, and their use has been gradually growing since the 1980s. Wavelength modulated fibre optic sensors among these modulation techniques, the first three modulation schemes are most commonly employed in a wide range ofapplications. An intensitymodulated optical fibre displacement sensor. We also presented a novel fiber optic sensor with a special construction like a spoke and the sensor was composed of a single mode emitting fiber as well as eight multimode receiving fibers. For example, an interferometric sensor can be regarded as a device measuring either a time delay or a phase lag. Serveral improvements in fiber optic sensing systems are disclosed. Pdf study of intensity modulated fiber optic sensor. Us7646946b2 intensity modulated fiber optic strain sensor. Appendix 1 gives examples of the types of modulating signals used for measurement purposes and most of these have been applied to modulate light in fibre optic sensor systems.
Referencing schemes for intensity modulated optical fiber sensor. Introduction to fiber optic sensors 7 intensity modulated fos phase modulated fos polarization modulated fos wavelength modulated fos phase modulated sensors usually use an interferometer and sense the output signal by comparing the phase of the received signal with a reference signal. Most common configurations of intensity modulated sensors applied in biomechanics are. Threeaxis fiber optic body force sensor for flexible manipulators. Paulo roriz et al fiber optic intensity modulated sensors. The concepts for intensity modulated fiber optic sensors. However, they remain unknown to many who work in the field.
Zehnder interferometer mzi is proposed and demonstrated. We theoretically and experimentally demonstrated an optical fiber magnetic field sensor. This document pdf may be used for research, teaching and private study. Intensitymodulated fiberoptic voltage sensors for power. Spatial division multiplexing based reflective intensity. Modulated principles of various intensity based sensors and their industrial applications are presented in this paper. One improvement incorporates a dielectric filter applied directly to the sensing end of an optical fiber detector which has the characteristic that it reflects back a reference light beam of one wavelength while passing a sensing signal of a different wavelength which is modulated in some predetermined fashion beyond the filter. This paper provides an overview of the intensity modulated and spectrometric fiber optic sensors and techniques to assess the condition of existing structures in order to enhance the durability of the new bridges, increasing lifetime and reliability and decreasing maintenance activities.
This resulting distortion of the sensing fiber causes the intensity of the light propagating through the sensing fiber to modulate in proportion to the magnitude of said acceleration event. The intensity of the light wave traveling through an optical fiber can be. The intensity of the light wave traveling through an optical fiber can be modified by microbending of the optical fiber, by a change in. Optical fiber sensors phase modulation sensors and. Optical engineering ebooks advanced search home ebooks fiber optic sensors. Intensity modulated optical measurements offer numerous. Memsbased reflective intensitymodulated fiberoptic sensor. A major benefit of extrinsic sensors is their ability to reach places which are otherwise inaccessible.
An intensitymodulated optical fibre displacement sensor with. Intensity modulated fiber optic strain sensor download pdf. Rf modulated fiber optic sensing systems and their applications. Intensity modulated fiber optic displacement sensors relate target displacement to a power measurement. Nevertheless, as optical fibers revolutionize the way of carrying data in. Fiber optic sensor for bacteria detection based on intensity modulated spr by monochromatic excitation. Memsbased reflective intensitymodulated fiberoptic. A strain sensor includes an optical fiber with at least one optical fiber, a reflector body with a reflective surface, a housing affixed to the optical fiber probe and to the reflector body. This is due to spontaneous response and ease in handling. The intensity modulation by the measurand can be made by creating leakages during the transmission, that is to say by bringing light out of the optical fiber. In this paper, among the various fiber optic sensor technologies, especially, technologies such as fiber grating sensors, fiber optic gyroscopes, and fiber optic current sensors are discussed with. A refractive index sensor based on an inline fabryperot interferometer is proposed and experimentally demonstrated. A novel intensity modulated optical fibre displacement sensor with convex reflector technology is described. Intensity modulation is one of the simplest to measure because it only requires a photodetector to measure the light intensity.
Optical fiber sensors can be divided into two basic categories. A highly sensitive intensitymodulated optical fiber magnetic field sensor based on the magnetic fluid and. We propose and demonstrate the use of laser intensity modulation for the multiplexing and demultiplexing of fiber bragg gratingbased ultrasound sensors. Intensity modulated fiber optic sensors have the many distinct advantages associated with fiber optics that makes.
A common form of the intensity modulated optical fibre sensor performs its measurement by making use of a pair of straight optical. A common form of the intensity modulated optical fibre sensor performs its measurement by making use of a pair of straight optical fibres with a plane reflector. Oct, 2012 fiber optic sensors have a set of properties that make them very attractive in biomechanics. The sensor principle itself is very simple when based on coupling between fibres, and coupling based intensity modulated sensors. The sensor consists of two multimode optical fibers with a spherical end, a quartz tube with dual holes, a silicon sensitive diaphragm, and a high borosilicate glass substrate hbgs. Intensity modulated optical fibre sensor, displacement sensor, convex reflector, blind region blind region or nonsensitive region 6, 7. A simple intensity modulated displacement sensor is proposed and demonstrated for sensing the concentration of glucose.
Osa intensitymodulated directional torsion sensor based. Osa multiplexing fiberoptic ultrasound sensors using laser. In recent years, intensity modulated fiber optic sensors have attracted significant interest due to their simple system, low cost, and high dynamic response. The method utilizes an intensity modulator to modulate the output power of the laser with a frequency much higher than that of the ultrasounds. Among the above mentioned fibre optic sensing schemes, intensity. The intensity of the light wave traveling through an optical fiber can be modified by microbending of the optical fiber. Among the above mentioned fibre optic sensing schemes, intensity modulation is the. Fibre optic sensor an overview sciencedirect topics. In the present paper, we have made use of a plastic optical fiber.
In optical communications, intensity modulation im is a form of modulation in which the optical power output of a source is varied in accordance with some characteristic of the modulating signal. Microbend optical fiber sensors have been explored for physical and chemical detection of parameters such as pressure, strain, displacement, vibration, temperature, intensity modulated microbend fiber optic sensor. Us6998599b2 intensity modulated fiber optic microbend. Us7646946b2 intensity modulated fiber optic strain. The envelope of the modulated optical signal is an analog of the modulating signal in the sense that the instantaneous power of the envelope is an. Passive optical ctpt epc intensity modulated optical. Study of intensity modulated fiber optic sensor effect of length of core exposed in guiding liquid. Fiber optic sensor an overview sciencedirect topics. Fiber optic magnetic field sensing is an important method of magnetic field monitoring, which is essential for the safety of civil infrastructures, especially for power plant. Pdf intensitymodulated fiber optic sensor for health.
Places where sensing happens extrinsic or hybrid fiber optic sensors intrinsic or allfiber fiber optic sensors characteristics of light modulated by environmental effect intensitybased fiber optic sensors spectrallybased fiber optic sensors interferometeric fiber optic sensors 7 college of. Throughout the late 1980s and 1990s the use of ramanbased. Sinead okeffe, elfed lewis, 20, intensity modulated fiber optic. Again a photoelastic force sensor modulates polarised light but the measurement can be in the form of an intensity. Since the late 1990s, the use of fiber optic sensors in the oil and gas industry has greatly expanded, especially for inwell monitoring applications 1,2. Since the intensity stabilization of light emitting diode led is the prime necessity of intensity modulated optical fibre sensors, the instrumentation for intensity stability of led is developed. Fibre optic intensity modulated sensors springerlink. Download pdf download citation view references email request permissions export to collabratec. Among them are those manipulating the change in light intensity coming out of the fiber as portion of the fiber is subjected to physical or chemical change. The light modulated in the sensing fiber propagates into the lead fiber. Intensity modulated sensors light is required to exit the fiber at the sensor from physics 5110 at indian institute of technology, chennai. Losscompensation of intensity modulating fiber optic sensors glenn beheim national aeronautics and space administration, lewis research center cleveland, ohio 445 and. With the development of optical fiber sensing technology, optical fiber sensors have increasingly become the research focus. The type of these fiber sensors intensity modulated sensors.
Based on the operating principle or modulation and demodulation process, a fiber optic sensor can be classified as an intensity, a phase, a frequency, or a. There are three basic techniques to create these leakages. Eustace john carroll university, physics department university hts. Two lasers are combined and injected into the sensor head. Wellwatcher dts fibre optic monitoring product sheet pdf.
Microbend optical fiber sensors have been explored for physical and chemical detection of parameters such as pressure, strain, displacement, vibration, temperature, intensity modulated microbend fiber optic sensor for respiratory monitoring and gating during mri. The simplest intensity modulated sensor architectures are not robust to environmental and hardware fluctuations, since such variability may cause changes in the measured power level that falsely indicate target displacement. Strain measurement by using phase modulated fiber optic sensors technology diyala journal of engineering sciences, vol. The principle of operation of a fiber sensor is that the modulates some transducer parameter of the optical system intensity, wavelength, polarization, phase, etc. Although, the accuracy of the sensor is far less that for interferometric sensors, the accuracy is more than sufficient for most process control situations. Fiber optic sensors for bridge monitoring journal of bridge. Fiber optic sensors fundamentals and applications, fourth edition, 2014 available at. Fiber optic sensors are playing important role in the field of sensors. A reflective intensity modulated fiber optic sensor based on microelectromechanical systems mems for pressure measurements is proposed and experimentally demonstrated. Intensity modulated fiber optic sensors overview, proceedings. Intensitymodulated microbend fiber optic sensor for.
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