Biodegradable microstructured polymer optical fibers have been created using synthetic biomaterials such as poly(L-lactic acid), poly(-caprolactone), and cellulose derivatives. Original processing techniques were utilized to fabricate a variety of biofriendly microstructured fibers that hold potential for in vivo light delivery, sensing, and controlled drug-release.
The backscattering spectrum of optical fiber has been measured by use 1427 nm Raman laser and Q8384 optical spectrum analyzer and Stokes and anti-Stokes ZX band backscattering spectrum has been first observed and discussed, ZX band frequency shift is 1THz, bandwidth 3THz(3dB). Optimum design of S-band negative dispersion DCF discrete fiber Raman amplifier has been researched by OPTIAMP DESIGN 3.3 SOFTWARE (made in Canada Optiwave Corporation) and gain spectrum and gain vs. power of DCF discrete fiber Raman amplifier have been measured, practical including Stokes ZX band backscattering gain effect. Pump on/off small signal gain is 13dB (pump power 700mw; fiber 5.1km) and gain band width is 88nm (1440nm-1528nm). The operation principle, configuration and performance of distributed fiber Raman temperature sensors system has been researched. Amplification of anti-Stokes spontaneity Raman scattering (ARS) effect of fiber and its temperature effect has been first observed and discussed. It has been applied to 30km distributed FRS system.
The optical fiber Raman temperature (OFRT) Lidar is a real time, on line and multi-point temperature measurement system. 30k spot temperature information on space field can be measured and located the position by 30km OFRT Lidar It is a new technology integration of optical-mechanic-electric and computer. The system can take real time, on line measurement of spatial temperature field. In the system, optical fibers are both transmission media and sensing media. The intensity of anti-stokes Raman backscattering of optical fiber is modulated by the spatial temperature field where the optical fiber is laid. After signal processing and demodulation, the information of temperature can be extracted from the noise and can be displayed in real time. In time domain, using the velocity of light wave in optical fiber, the time interval ofback-direction light wave and optical fiber OTDR technology The amplification of anti-stokes Rairan spontaneous scattering (ARS) and the temperature effect have been first observed and applied to OFRT Lidar. The performance of OFRT Lidar is following: fiber length : 25.2km; temperature measuring range: O-lOOC(can be expand) temperature uncertainty: 2 C : temperature resolution: 0. 1 ; spatial resolution: Sm: measurement time: 5mm; Main unit operation temperature range: O—40t .The optical fiber sensor probes and the software for signal processing are also discussed. Keywords: Optical Fiber Raman Temperature (OFRT) Lidar, Optic Time Domain Reflection (OTDR),distributed optical fiber Raman photons temperature sensors, the temperature effect of Raman backscattering, Rayleigh backscattering, ZX band backscattering spectrum, optical fiber sensor probe.
The distributed optical fiber Raman Photons Temperature Sensors (DFRS) is a real time, on line and multi-point (30k points) measuring system for multi-parameter measurement of temperature etc. According to temperature effect of optical fiber Raman backscattering, the intensity of anti-stokes Raman backscattering of optical fiber is modulated by the spatial temperature field where the optical fiber is laid. Then after signal processing and demodulation, the information of temperature can be extracted from the noise and can be displayed in real time. It is a typical optical fiber sensors measuring network. In time domain, using the velocity of light wave in optical fiber, the time interval of back-direction light wave and optical fiber OTDR technology, the DFRS can locate the temperature spots. In this case, it is a typical optical fiber laser temperature radar system as well. The backscattering spectrum of optical fiber has been measured by fiber laser and optical spectrum analyzer. Raman backscattering spectrum and ZX band backscattering spectrum has been first observed. The amplification of anti-stokes Raman spontaneous scattering (ARS) and the temperature effect have been first observed and applied to DFRS. The performance of DOFS is following: fiber length : 25.2km;temperature measuring range: 0-1000C(can be expand) temperature uncertainty: ±200C : temperature resolution: 0. 1; spatial resolution: 5m: measurement time: 10mm; Main unit operation temperature range: 0—400C . The optical fiber sensor probes and the software for signal processing are also discussed.
The mini pulse laser rangefmder (LRF) uses semiconductor laser as its source. This kind of LRF has property of safe, small size and low cost. It can be applied in sports and some filed of engineering just like wire layout. To extend its application field, the measurement parameter, which is now 1km in maximum range and 1m in accuracy at one measurement, need to be improved. The raise time of pulse can be more sharp, the speed response of receiver can be more quickly and the efficient arithmetic should be taken.
This paper briefly introduces the operation principle and configuration of distributed optical fiber sensor (DOFS) system. A new demodulation method that uses Rayleigh back scattering photon flux to demodulate Raman back scattering photon flux is put forward, and the advantages of this new method are discussed. Methods to measure temperature, strain and pressure at the same time are researched. The performance of DOFS is following: fiber length: 10.2 km; temperature uncertainty: +/- 2 degree(s)C: temperature resolution: 0.1 degree(s)C; spatial resolution: 4m: measurement time: 5 min; Main unit operation temperature range: 0 - 40 degree(s)C. The DOFS system have been applied to coal mine.
The temperature effect of fiber optics Raman back-scattering have been researched at high temperature (1000 degree(s)C) condition. A distributed fiber optics Raman and Rayleigh back-scattering sensor measuring network have been design and fabricated. The performance of high temperature measuring network is following: temperature measuring range: 0-1000 degree(s)C; temperature uncertainty: <+/- 30 degree(s)C; temperature resolution: 1 degree(s)C; Spatial resolution: 8<m Measuring time: 40s; Fiber length: 100m-10km (according to user need). The stress change of optical cable can be toke out by the measuring network.
KEYWORDS: Optical fibers, Temperature metrology, Time metrology, Photons, Raman spectroscopy, Temperature sensors, Signal detection, Spatial resolution, Raman scattering, Signal to noise ratio
The operation principle, technique character and measuring method of 10 km LDOFTS are discussed. The testing result of 10 km LDOFTS is given in this paper.
A new sampling correct technology of distributed optical fiber temperature sensor (DOFTS) has been researched to eliminate the instability of DOFTS system that caused by the change of environment temperature, gain of amplifier and voltage of power supply. Put the optical sampling loop into a constant temperature thermostat. A computer automatically corrects signal voltage of every point. Thus the stability of the system is improved.
The DOFTS system that has applied to temperature automatically alarm system of coal mine and tunnel has been researched. It is a real-time, on line and multi-point measurement system. The wavelength of LD is 1550 nm, on the 6 km optical fiber, 3000 points temperature signal is sampled and the spatial position is certain. Temperature measured region: -50 degree(s)C--100 degree(s)C; measured uncertain value: +/- 3 degree(s)C; temperature resolution: 0.1 degree(s)C; spatial resolution: <5 cm (optical fiber sensor probe); <8 m (spread optical fiber); measured time: <70 s. In the paper, the operated principles, underground test, test content and practical test results have been discussed.
The implementation of an ultrasonic method of evaluation of composite plates requires a good knowledge of the interaction of ultrasonic beam emitted by the transducers, with such a plate immersed in a fluid. The model of ultrasonic propagation in anisotropic multilayered materials developed here makes the study of this interaction possible. The interaction of ultrasonic beams with fluid-loaded multilayered anisotropic structures is treated numerically by combining the propagator matrix and the angular spectrum decomposition technique. The numerical model developed during the course of investigation is used to calculate the reflection and transmission profiles for a Gaussian beam incident on a multilayered composite. The model allows the calculations of the reflected and transmitted ultrasonic fields for a multilayered composite, absorbing or not. The emphasis is placed on the regime of nonspecular reflection that is characterized by the strong cooling between the specularly reflected beam and the leaky waves supported by the structure corresponding to the incidence in the vicinity of multilayered Rayleigh modes.
In the 6km DOFRPS system, the 1550nm LD is excited photon source. The spontaneous Raman scattering photon are carriers of temperature signal and the Rayleigh scattering photon are carriers of strain and pressure signal. On the 6km optical fiber, the 3000 point temperature, strain and pressure are measured on time and the position of measured local domain have been determined by OTDR technique. The optimum design of 6km LD DOFRPS system and the configuration of the system are discussed in the paper.
In this paper, the Nd:YAG laser engraving system is studied for the purpose of engraving image, figure, and characters on the surface of metal, ceramic, plastic, leather, etc. First of all, the high repetition and high power Nd:YAG laser is set up; secondly, the 2-mirror 2-axis optic scan system is analyzed and designed; third, the software is developed to control the laser beam in vector mode or in dot matrix mode. The expanded laser beam is directed toward the worksurface through a f-(theta) lens by computer controlled X and Y axis mirror, and moves in a fixed path, a mark is engraved or marked. As a result, the marking field of 100 X 100mm and spot size of 0.088mm are obtained.
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