The method of sensing light rays is known as optical sensing. A fiber are used because of narrow size, no electric power is used. Intrinsic semiconductor and extrinsic semiconductor the semiconductor is divided into two types. In this study, fbg, a type of gratingbased fos is used over another type of gratingbased sensor configuration as fbg is simple inherent selfreferencing. The optical sensor types include point sensor,distributed sensor,extrinsic sensor,intrinsic sensor,through beam sensor,diffuse reflective sensor and retroreflective sensor. Based on modeualtion and demodulation process of sensor intensity, phase, frquency, polarization etc. A patchtype extrinsic fabryperot interferometric fiber optic sensor and a realtime structural vibration monitoring method using the same are disclosed.
Abstract this paper presents an overview of fiber optic sensor technology,basic classifications of optic sensors, namely the extrinsic sensors and the intrinsic sensors and their operation principles, also discussed the basic functions of optical fiber sensors. Most commonly available fibers are based on silica, and the faraday effect in silica is weak. Optical fiber sensing technology science publishing group. The fiber sensor can be either an intrinsic oneif the modulation takes place directly in the fiberor extrinsic. Product segments extrinsic fiber optic sensors, and intrinsic fiber optic sensors. This paper describes the use of the first and second optical return paths in a moderatetohigh finesse fabryperot sensor to measure the absolute phase in extrinsic fabryperot interferometry efpi sensors. The best example of this sensor is the inside temperature measurement of the aircraft jet engine that uses a fiber to transmit a radiation into a radiation pyrometer, which is located outside of the engine. A pathmatched differential interferometry pmdi using a highfinesse efpi sensors, a lowfinesse fabryperot readout interferometer and a broadband light source consisting of amplified. Fiber strain sensor and system including one intrinsic and. Intrinsic fiber optic sensor extrinsic sensors are distinguished by the characteristic that the sensing takes place in a region outside the fiber as shown in fig. Extrinsic optical sensor the figure1 depicts extrinsic optical sensor. The extrinsic fiber optic sensor recited in claim 2 wherein said second optical fiber is connected to a second extrinsic fiber optic sensor as an inputoutput optical fiber.
In this paper we discuss optical sensors and their application in medical field. Help us write another book on this subject and reach those readers. Losses in fiber optics attenuation, dispersionintermodel, intramodel, bend lossmicro macro scattering losseslinear, non linear, absorption link budget, power budget block diagram and working of otdr. A fiber is placed between two plates with rough surfaces. The fiber sensor can be either an intrinsic oneif the modulation takes place directly in the fiberor extrinsic, if the. A compact, dualprobe, fiberized sagnac ultrasound sensor sus capable of detecting ultrasonic waves of various types is described. Conference on applications of optics and photonics, costa mf. Absolute phase measurement in extrinsic fabryperot optical. Each sensing region has partially reflective boundaries and produces an.
The transmission and reflection properties of this system are fully categorized. Liquid pressures act on the mechanical construction to change the cavity length, resulting in differential phase shifts that may be observed as variations of the output signal intensity. An optical sensor is a sensor which uses an optical fiber as a sensing component. An optical fiber liquidlevel sensor based on an extrinsic fabryperot fp cavity is proposed and demonstrated. The present invention is directed toward an interferometric sensor that permits the simultaneous measurement of a change in more than one environmental condition. Us6671055b1 interferometric sensors utilizing bulk sensing. One is intrinsic semiconductor and other is an extrinsic semiconductor. The optical strain sensor 50 has an optical fiber or waveguide 52, connected to one end 54 of a first extrinsic fabryperot interferometer efpi 56.
In general, optical fiber sensors may be categorized under two headings according to their operation 24, 23, 24. Optical fiber sensors offer attractive characteristics that make. Opticalfiber sensors, sensitivity, intrinsic, extrinsic, gyroscope sensor, kerr nonlinearities. Pdf on feb 22, 2012, sylvain lecler and others published intrinsic optical fiber sensor find. Extrinsic fiber optic sensors utilize an optical fiber cable, usually a multimode one, to transmit modulated light by either a nonfiber optical sensor, or else an electronic sensor linked to an optical transmitter. An extrinsic optical fibre sensor employing a partially.
An extrinsic xray fiber sensor with improved sensitivity is presented. Intrinsic sensors utilize a change that takes place within the fiber itself. In this type of sensors the fiber acts only as a data transmission line. This paper presents the newly developed transmission. Thus, in an intrinsic fp sensor, the fiber contains the resonant cavity. This page covers optical sensor basics and optical sensor types including its applications and working operation. Sensors which modulate light intensity tend to use mainly multimode fibers, but only monomode cables are used to modulate other light parameters. Intrinsic fiber optic sensor extrinsic sensors are distinguished by the characteristic that the sensing takes place in a region outside the. The optical sensor types include point sensor, distributed sensor, extrinsic sensor, intrinsic sensor, through beam sensor, diffuse reflective sensor and retroreflective sensor. However, they have the disadvantage that the distinction of strain direction of efpi is difficult because of measurement method by only fringe counting. Explain about the term extrinsic fiber optic sensors, physics.
Domaski acultfy of physics, warsaw university of ecthnology, koszykowa 75, 00662 warszawa, poland the paper presents optical ber sensor designed for medical audiometric measurements. According to the role optical fiber plays, fiber sensing can be divided into. Unfortunately, the output of many sensors is not in a form that can be transmitted by a fiber optic cable, and conversion into a. A fiberoptic current sensor for lightning measurement. Yet another type of intrinsic sensor uses cable where the core and cladding have similar. An intrinsic fiberoptic sensor for structure lightning. When light beam leaves the fiber cable and get changed due to object before it reaches to the optical detector end then it is known as extrinsic optical sensor.
The patchtype extrinsic fabryperot interferometric fiber optic sensor is provided by combining the existing efpi extrinsic fabryperot interferometer fiber optic sensor with a directiondetecting sensor which can acquire direction. In the same way, these sensors can also be used to measure the internal temperature of the transformers. Main objectives model the movement of light ray inside the optical. In an intrinsic optical fiber sensor, the tran sducer converts the physical va lue to be measured into an optical information. On the other hand, in an intrinsic fiber optic sensor one or more of the physical properties of the fiber undergo a. Figure 1 shows an extrinsic sensor which consists of an optical fiber that transmits. Extrinsic and intrinsic fiber optic sagnac ultrasound. Within the extrinsic sensors category, two subgroups can be distinguished, depending on the chemical agent that. This type of sensor is able to detect stresses that may have a lasting impact on structures. Extrinsic sensors are, in general, analogous to photoelectric controls with the potential problems of being affected by dirt, dust, vibration, and alignment. In an intrinsic sensor, the fiber itself is the sensing.
Intrinsic optical fiber sensor, fiber optic sensors, moh. The primary focus of the sensor is to measure low doses of ionizing xray radiation. A quadrature phaseshifted extrinsic fiber optic sensor for the detection of the amplitude and the relative polarity of dynamically varying displacement comprising. In particular, it uses an optical fiber as the sensing element, called an intrinsic sensor, or uses it to transport signals from the.
This is in contrast to extrinsic sensors, in which the change is outside the fiber and the fiber itself remains unchanged. A study on the development of transmissiontype extrinsic. Fiber optic sensor an overview sciencedirect topics. How to reduce various types of losses in optical fiber. Us6671055b1 interferometric sensors utilizing bulk. Axial offset effects upon optical fiber sensor and splice.
An example is a pressure sensor based on microbending of the fiber. Light is transmitted along multimode graded index fibre into a grinrod lens coupler system. Apart from the intrinsic fiber losses, there are some other types of losses in the optical fiber that contribute to the link loss, such as splicing, patch connections, bending, etc. This project develops an intrinsic, singlemode, polymer optical fiber pof used as a largestrain sensor for applications such as health monitoring of a civil infrastructure subjected to earthquake loading. Extrinsic sensors have successfully been used in real applications, and some working networks for monitoring organic gases based on extrinsic optical fiber sensors are actually in use. Intrinsic sensors can modulate the intensity, phase, polarization, wavelength or transit time of light. The optical sensor types include point sensor,distributed sensor, extrinsic sensor, intrinsic sensor,through beam sensor,diffuse reflective sensor and retroreflective sensor. An optical strain sensor 50 that overcomes the problems of the prior art is shown in fig. Pdf radiation dosimeter using an extrinsic fiber optic sensor. Optical fiber is an intrinsic part of the lighttransmitting concrete building product litracon. A particularly useful feature of intrinsic fiber optic sensors is that they can, if required. In contrast, in extrinsic sensor optical fiber is only used for relaying signal from a remote sensor.
The patch type extrinsic fabryperot interferometric fiber optic sensor is provided by combining the existing efpi extrinsic fabryperot interferometer fiber optic sensor with a directiondetecting sensor which can acquire direction. Extrinsic and intrinsic fiber optic sagnac ultrasound sensors. Fiber attenuation, which is also called signal loss or fiber loss, is the consequence of the intrinsic properties of an optical fiber multimode and single mode fiber. The conventional reflectiontype extrinsic fabryperot interferometric efpi optical fiber sensor has good sensitivity and resolution compared with other types of optical fiber sensors. On the other hand, in an intrinsic fiber optic sensor one or. The interferometric sensor comprises an optical fiber and a plurality of sensing regions positioned in an operable relationship to the optical fiber. Extrinsic optical fiber sensor for medical audiometric. Extrinsic optical sensor vs intrinsic optical sensor. Qingxu yu et al pressure sensor based on the fiber optic extrinsic fabryperot interferometer 81 sensitivity of 31 mvpa in the frequency range from 100hz to 12. Labview applications for optical amplifier automated.
Based on the modulation technique, fibre optic sensors can be classified into 5 different groups. A microdisplacement sensor consisting of a fiberloop made with a tapered fiber is reported. The pure form of the semiconductor is known as the intrinsic semiconductor and the semiconductor in which intentionally impurities is added for making it conductive is known as. The fiber sensor can be either an intrinsic oneif the modulation takes place directly in the fiber or extrinsic, if the modulation is performed by some external transducer as depicted in fig. A fiberoptic sensor is a sensor that uses optical fiber either as the sensing element intrinsic sensors, or as a means of relaying signals from a remote sensor to the electronics that process the signals extrinsic sensors. A fiber optic sensor is a sensor that uses optical fiber either as the sensing element intrinsic sensors, or as a means of relaying signals from a remote sensor to the electronics that process the signals extrinsic sensors. Intrinsic, singlemode polymer optical fiber sensors for. Highly sensitive extrinsic xray polymer optical fiber. Fp sensors can have extrinsic or intrinsic cavities, depending on the. If the optical fiber is only used to transmit the light, we talk about an. Depending on the usage, fiber optic sensors can be divided into extrinsic or hybrid an d intrinsic or allfiber types. In 12 an ultrasensitive intrinsic fiber sensor based on the macrobending loss at 1. An intrinsic fiberoptic single loop microdisplacement sensor.
In fact, two kinds of optical fiber sensors arised in the market. Qingxu yu et al pressure sensor based on the fiberoptic extrinsic fabryperot interferometer 81 sensitivity of 31 mvpa in the frequency range from 100hz to 12. Extrinsic and intrinsic types of fiber optic sensors. The distance l can be measured with this type of optical sensor as shown. Introduction to fiber optic sensors and their types. Pdf radiation dosimeter using an extrinsic fiber optic. The other end 58 of the first efpi 56 is connected to an intrinsic fabryperot interferometer ifpi 60. Intrinsic optical fiber sensor 55 optical fiber sensor is a system where information is created in the optical path way due to an interaction with a physical phenomenon to be measured and before its transmission to a detector using one or several optical fibers. Extrinsic fabryperot cavity optical fiber liquidlevel sensor.
The sensor type used for optical sensing is known as optical sensor. It is based on the principle of measuring analog attenuation. In this case the fibre merely acts as a conduit to transport light signal to and from the sensor head. A novel extrinsic optical fibre displacement sensor is described which intensity modulates an incoherent light source. The sensor operation is based on the interaction between the fundamental cladding mode propagating through the taper waist and higher order cladding modes excited when the taper is deformed to form a loop. An example is the moving grating fiber optic sensor 3. Extrinsic sensing take place outside of fiber where, fiber only serve as conduit to transmit light to and from the sensing. Pdf fiber optic sensors and their applications researchgate. Based on modulation and demodulation process of sensor intensity, phase, frequency, polarization etc. In reference, an intrinsic microdisplacement sensor based on a two core fiber is proposed, where the sensitivity depends on the bending deformation suffered by multiple fiber loops. Applying fiber optical acoustic sensor to photoacoustic spectrometer, an alloptical pas system is realized recently.
In both types of sensors the measurand is used to modulate the light by intensity, phase, polarization, wavelength or by frequency. In this case, the sensor is known as an intrinsic sensor. These sensors provide excellent protection of measurement signals against noise corruption. Pressure sensor based on the fiberoptic extrinsic fabry. In the former case the optical fiber forms the function of transmitting the. Intrinsic optical fiber sensor 55 optical fiber sensor is a system where informat ion is created in the optical path way due to an interaction with a physical phenomenon to be measured and before its transmission to a detector using one or several optical fibers. What is intrinsic semiconductor and extrinsic semiconductor. Unlike the wellknown rogowski coil, the opticalfiber sensor is selfintegrating thus no integrator is needed, and the. Optical fibers are also attractive for applications in sensing, control and instrumentation. Applying fiber optical acoustic sensor to photoacoustic spectrometer, an all optical pas system is realized recently. The fp cavity consists of the end of the singlemode optical fiber and the elastic silicon layer. Extrinsic optical fiber sensor for medical audiometric applications k. A patch type extrinsic fabryperot interferometric fiber optic sensor and a realtime structural vibration monitoring method using the same are disclosed. Explain about the term extrinsic fiber optic sensors.
Keywordsoptical sensor, optical sensor use in medical field i. The main advantages of the proposed device are 1 the ability to detect ultrasonic waves on the surface extrinsic mode as well as in the interior of structures intrinsic mode. The second type, the extrinsic sensor, uses the optical fiber purely as a means of transmitting light to and from the sensor. Sensitivity improvement has been accomplished by modifying the fiber tip in two ways, either by thermomechanical tapering of chemical etching. It can be a thermooptic, elastooptic, magnetooptic. Extrinsic fiber optic sensors utilize an optical fiber cable, usually a multimode one, to transmit modulated light by either a non fiber optical sensor, or else an electronic sensor linked to an optical transmitter.
Extrinsic fiber optic sensors use a fiber optic cable, normally a multimode one, to transmit modulated. A fiber optic sensor is a sensing device that uses fiber optic technology for measuring physical quantities such as temperature, pressure, strain, voltages and acceleration, to name a few. With extrinsic sensors, light leaves the fiber and is blocked or reflected before going back into the fiberoptic system. Oct 28, 1997 an optical strain sensor 50 that overcomes the problems of the prior art is shown in fig. A novel extrinsic optical fiber xray dosimeter for biomedical applications is presented in this paper. The conventional reflection type extrinsic fabryperot interferometric efpi optical fiber sensor has good sensitivity and resolution compared with other types of optical fiber sensors. Fiberbased fabryperot fp interferometers share the advantages of all types of optical fiber. Sylvain lecler and patrick meyrueis february 22nd 2012. In this type, light rays do not come out of fiber cable. One such application is shown in the figure2 where in due to pressure applied between the two plates will change the light beam and hence pressure is measured. Study of multimode extrinsic fabryperot interferometric. The fiber sensor can be either an intrinsic oneif the modulation takes place directly in the fiberor extrinsic, if the modulation is performed by some external transducer as depicted in fig.
The pure form of the semiconductor is known as the intrinsic semiconductor and the semiconductor in which intentionally impurities is added for making it conductive is known as the extrinsic semiconductor. If the optical fiber is only used to transmit the light, we talk about an extrinsic. The developed device is based on an inorganic scintillator terbium doped gadolinium oxysulfide attached to a polymer fiber tip. For decades, optical sensors have been finding their way into an increasing number of applications. This type of optic sensors, measure and modulates the intensity of the transmitted light through the fiber and devotion in intensity is measured using a detector placed. Optical fiber can also be used in structural health monitoring. The reflected light from the target is sensed by a detector.
409 1400 1386 888 263 867 624 1339 988 818 478 244 953 85 689 344 484 310 543 1044 162 997 731 979 1345 458 30 272 1498