Imaging Spectroscopy Using Fiber Optics

1997 ◽  
Vol 3 (S2) ◽  
pp. 845-846
Author(s):  
S. Michael Angel ◽  
H. Trey Skinner ◽  
Brian J. Marquardt
Keyword(s):  
Optical Fiber ◽  
Fiber Optics ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Imaging System ◽  
Single Point ◽  
Imaging Spectroscopy ◽  
Small Diameter ◽  
Imaging Spectrometer ◽  
Remote Spectroscopy

Optical fiber probes are routinely used with optical spectrometers to allow measurements to be made on remotely located samples. In most of these systems, however, the optical fibers are used as non-imaging “light pipes” for the transmission of laser light, and luminescence or Raman signals to and from the sample. Thus, while these systems are suitable for remote spectroscopy, they are limited to single-point measurements. In a recent paper, we showed that a small-diameter (i.e., 350 μm) coherent optical fiber bundle can be combined with an AOTF-based imaging spectrometer for fluorescence and Raman spectral micro-imaging with increased flexibility in terms of sample positioning and in-situ capabilities. The previous paper described the operation of the fiber-optic microimaging probe and AOTF imaging system and showed preliminary Raman and fluorescence images for model compounds with 4 μm resolution. We have extended this work to include a discussion of the lateral and vertical spatial resolution of the fiber-optic microprobe in a non-contact proximity-focused configuration.

scholarly journals Analysis of Curvature in Fiber Optic Cable for Macrobending-Based Slope Sensor

2021 ◽  
Vol 3 (1) ◽  
pp. 45-56
Author(s):  
Imam Mulyanto
Keyword(s):  
Fiber Optics ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Laser Light ◽  
Laser Intensity ◽  
Single Mode ◽  
Power Losses ◽  
Fiber Optic Cable ◽  
Power Meter ◽  
Working Principle

The analysis of fiber optics for macro bending-based slope sensors using SMF-28 single-mode optical fibers has been successfully conducted. Fiber optics were treated to silicon rubber molding and connected with laser light and power meters to measure the intensity of laser power generated. The working principle was carried out using the macrobending phenomenon on single-mode optical fibers. The intensity of laser light in fiber optic cables decreases in the event of indentation or bending of the fiber optic cable. Power losses resulting from the macrobending process can be seen in the result of the information sensitivity of fiber optics to the change of angle given. From the results of the study, the resulting fiber optic sensitivity value is -0.1534o/dBm. The larger the angle given, the lower the laser intensity received by the power meter.

Automated Fiber-Optic System for Monitoring the Stability of the Pit Quarry Mass and Dumps

2021 ◽  
pp. 19-26
Author(s):  
А.D. Меkhtiyev ◽  
◽  
E.G. Neshina ◽  
P.Sh. Madi ◽  
D.A. Gorokhov ◽  
...  
Keyword(s):  
Rock Mass ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Light Wave ◽  
Single Mode ◽  
Fiber Optic Sensors ◽  
Fiber Optic Sensor ◽  
Laboratory Sample ◽  
Single Mode Optical Fiber

This article ls with the issues related to the development of a system for monitoring the deformation and displacement of the rock mass leading to the collapse of the quarry sides. Monitoring system uses point-to-point fiber-optic sensors. Fiber-optic sensors and control cables of the communication line are made based on the single mode optical fibers, which allows to measure with high accuracy the deformations and displacements of the rock mass at a distance of 30-50 km. To create fiber-optic pressure sensors, an optical fiber of the ITU-T G. 652.D standard is used. Laboratory sample is developed concerning the point fiber-optic sensor made based on the two-arm Mach-Zender interferometer using a single mode optical fiber for monitoring strain (displacements) with a change in the sensitivity and a reduced influence of temperature interference leading to zero drift. The article presents a mathematical apparatus for calculating the intensity of radiation of a light wave passing through an optical fiber with and without mechanical stress. A laboratory sample of single mode optical fibers based on the Mach-Zender interferometer showed a fairly high linearity and accuracy in the measurement and can be used to control the strain of the mass after appropriate refinement of its design. Mathematical expressions are also given for determining the intensity of the light wave when the distance between the fixing points of a single mode optical fiber changes depending on the change in the external temperature. A diagram for measuring strain using a point fiber-optic strain sensor is developed. Hardware and software package is developed, which can be used to perform a number of settings of measuring channels. The work is aimed at solving the production problems of the Kenzhem quarry of AK Altynalmas JSC.

Integrated Fiber Optic Sensors For Nondestructive Characterization Of Concrete Structures

1997 ◽  
Vol 503 ◽  
Author(s):  
F. Ansari
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Optical Fiber Sensor ◽  
Fiber Optic Sensors ◽  
Fiber Sensors ◽  
Fully Integrated ◽  
Integrated Optical ◽  
Concrete Elements

ABSTRACTIt is possible to monitor the initiation and progress of various mechanical or environmentally induced perturbations in concrete elements by way of fully integrated optical fiber sensors. Geometric adaptability and ease by which optical fibers can be embedded within concrete elements has led to the development of a number of innovative applications for concrete elements. This article is intended for a brief introduction into the theories, principles, and applications of fiber optic sensors as they pertain to applications in concrete.. However, due to the fact that the transduction mechanism in optical fibers is invariant of the materials employed, the principles introduced here also correspond to other structural materials. The only application related differences among various materials pertain to sensitivity and choice of optical fiber sensor types.

Distributed Fiber Optic Strain Sensing with Embedded Small-Diameter Optical Fibers in CFRP Laminate

2007 ◽  
Vol 334-335 ◽  
pp. 1013-1016
Author(s):  
Tadahito Mizutani ◽  
Takafumi Nishi ◽  
Nobuo Takeda
Keyword(s):  
Spatial Resolution ◽  
Optical Fibers ◽  
Composite Structures ◽  
Fiber Optic ◽  
Current Trend ◽  
Small Diameter ◽  
Long Distance ◽  
Distributed Sensors ◽  
Cfrp Laminate ◽  
Sensing Applications

Although demand for composite structures rapidly increase due to the advantages in weight, there are few effective assessment techniques to enable the quality control and guarantee the durability. In particular, an invisible microscopic damage detection technology is highly required because damages such as transverse cracks, debondings, or delaminations can lead to the critical failure of the structures. Among many non-destructive evaluation (NDE) methods for composite structures, fiber optic sensors are especially attractive due to the high sensitivity, the lightweight, and the small size. In the current trend of the structural health monitoring technology, fiber Bragg gratings (FBG) sensors are frequently used as strain or temperature sensors, and Brillouin scattering sensors are also often used for a long distance distributed measurement. The Brillouin distributed sensors can measure strain over a distance of 10km while a spatial resolution was limited to 1m. Some novel sensing method is proposed to improve the spatial resolution. The pulse-prepump Brillouin optical time domain analysis (PPP-BOTDA) is one of the latest distributed sensing applications with a cm-order high spatial resolution. The PPP-BOTDA commercial product has the spatial resolution of 10cm, and can measure the strain with a precision of ±25og. This precision, however, can be achieved by using conventional single-mode optical fibers. In our research, small-diameter optical fibers with a cladding diameter of 40om were embedded in the CFRP laminate to avoid the deterioration of the CFRP mechanical properties. Thus, in order to verify the performance of PPP-BOTDA, the distributed strain measurement was conducted with the small-diameter optical fibers embedded in the CFRP laminate.

Lensed Plastic Optical Fiber with a Convexo-Concave Fiber Endface for Coupling Laser Diodes With Plastic Optical Fiber

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Yih-Tun Tseng ◽  
Shu-Ming Chang ◽  
Sheng-He Huang ◽  
Wood-Hi Cheng
Keyword(s):  
Optical Fiber ◽  
Light Source ◽  
Optical Fibers ◽  
Transmission Rate ◽  
Coupling Efficiency ◽  
Small Diameter ◽  
Plastic Optical Fiber ◽  
Graded Index ◽  
Coupling Laser ◽  
Working Distance

This work presents a novel lensed plastic optical fiber (POF), efficiently coupled with a light source. A convexo-concave plastic lens (CCPL) was bound to a flat-end plastic optical fiber using laser transmission welding (LTW) to form a convexo-concave-shaped fiber endface (CCSFE). The novel lensed plastic optical fiber has a longer working distance and a higher coupling efficiency than conventional lensed plastic optical fibers. 850 nm fiber is often used in high-power 2.5 Gb/s transmission rate. Experimental POF is perfluorinated POF, 62.5–500 μm diameter, 850∼1300 μm wavelength, 10 dB/km power loss rate, 2.5 Gb/s transmission rate. Because of the small diameter of POF, it is difficult to couple between the light source and POF. Therefore, it is important to develop a lensed fiber structure to increase the coupling efficiency. Experiments indicate that the coupling efficiency between a laser diode at a wavelength of 850 nm and a graded-index POF is as high as 85% with a long working distance of 250 μm. The measured tolerance, in relation to the lateral and vertical displacements and tilt, are satisfactory for practical active alignment.

scholarly journals Curvature Analysis in Fiber Optic Cables as a Tilt Sensor Based on Macro Bending

2020 ◽  
Vol 2 (2) ◽  
pp. 91-99
Author(s):  
Imam Mulyanto
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Laser Light ◽  
Single Mode ◽  
Fiber Optic Cable ◽  
Power Meter ◽  
Curvature Analysis ◽  
Bending Process ◽  
Tilt Sensor

The test has been successfully carried out on optical fibers to be used as a macrobending tilt sensor using SMF-28 single mode optical fiber. The optical fiber was molded with silicon rubber, then connected to a laser light and a power meter to see the intensity of the laser power produced. The principle is carried out using the macro bending phenomenon on single mode optical fibers, where the laser light intensity in the fiber optic cable will decrease if there is a bend or bending in the fiber optic cable. We can observe the power loss resulting from the macro bending process to find out how sensitive the optical fiber is to changes in a given angle. The resulting optical fiber sensitivity value is -0.1534o/dBm.

Evanescent Wave Absorption Spectroscopy by Means of Bi-Tapered Multimode Optical Fibers

1998 ◽  
Vol 52 (4) ◽  
pp. 546-551 ◽  
Author(s):  
Anna Grazia Mignani ◽  
Riccardo Falciai ◽  
Leonardo Ciaccheri
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Absorption Spectroscopy ◽  
Evanescent Wave ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Experimental Results ◽  
Multimode Optical Fiber ◽  
Wave Absorption ◽  
Reproducible Technique

This paper discusses the theoretical and experimental implications of tapering a multimode optical fiber with a view to its use in evanescent wave absorption spectroscopy. Good experimental results are obtained, showing the possibility of quadruplicating the absorbance efficiency. This easy and reproducible technique for taper fabrication is suitable for the implementation of both probes for spectroscopy and chemically assisted fiber-optic sensors.

scholarly journals Evaluation of the Detection Efficiency of LYSO Scintillator in the Fiber-Optic Radiation Sensor

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Chan Hee Park ◽  
Arim Lee ◽  
Rinah Kim ◽  
Joo Hyun Moon
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Detection Efficiency ◽  
Radiation Detection ◽  
Refraction Index ◽  
Fiber Optic Sensor ◽  
Optic Radiation ◽  
Spent Fuel ◽  
Radiation Sensor

The aim of this study was to develop and evaluate fiber-optic sensors for the remote detection of gamma rays in areas that are difficult to access, such as a spent fuel pool. The fiber-optic sensor consists of a light-generating probe, such as scintillators for radiation detection, plastic optical fibers, and light-measuring devices, such as PMT. The (Lu,Y)2SiO5:Ce(LYSO:Ce) scintillator was chosen as the light-generating probe. The (Lu,Y)2SiO5:Ce(LYSO:Ce) scintillator has higher scintillation efficiency than the others and transmits light well through an optical fiber because its refraction index is similar to the refractive index of the optical fiber. The fiber-optic radiation sensor using the (Lu,Y)2SiO5:Ce(LYSO:Ce) scintillator was evaluated in terms of the detection efficiency and reproducibility for examining its applicability as a radiation sensor.

Sign in / Sign up

Export Citation Format

Share Document