Estimation of metal surface roughness using fiber optic displacement sensor

A fiber optic displacement sensor is proposed to estimate the roughness of metal surface using the intensity modulation technique. A light beam is launched onto the metal surface via a bundled fiber. The reflected light from the surface is collected and then routed to a silicon detector. The level of roughness for aluminum, stainless steel and copper samples are estimated to be approximately 27, 26, and 20% respectively by fixing the object within the linear range of the sensor. The output voltages are measured as a function of lateral distance to estimate the roughness of the surface.     

Shaft runout inspection by a fiber optic displacement sensor

A reflective fiber optic displacement sensor has been developed and calibrated to gauge form and axis position of shafts during rotation. A technique has been implemented to determine the deviation of the actual shaft form from its nominal circular cross section (the off-round error) and the departure of the rotation axis from the geometric axis (the eccentric error). The sensor is simple, has acceptable accuracy for applications to mechanical engineering, is capable of monitoring shafts during rotation, and has potential for gauging parts on the production line.     

LS-SVM-based surface roughness prediction model for a reflective fiber optic sensor

Reflective fiber optic sensors have advantages for surface roughness measurements of some special workpieces,but their measuring precision and efficiency need to be improved further. A least-squares support vector machine(LS-SVM)-based surface roughness prediction model is proposed to estimate the surface roughness, Ra, and the coupled simulated annealing(CSA) and standard simplex(SS) methods are combined for the parameter optimization of the mode. Experiments are conducted to test the performance of the proposed model, and the results show that the range of average relative errors is-4.232%–2.5709%. In comparison with the existing models, the LS-SVM-based model has the best performance in prediction precision, stability, and timesaving.     

纳米级光纤位移传感器

介绍利用高斯光束干涉测微小位移的方法,利用该方法设计了纳米级光纤位移传感器,测试了该传感器的位移响应与频率响应.     

Simple design of optical fiber displacement sensor using a multimode fiber coupler

A simple design sensor is demonstrated using a fabricated multimode plastic fiber coupler in conjunction with reflective intensity modulation technique. The performances of this sensor are investigated for different light sources. This sensor uses only one fiber for sending and receiving the light and therefore only the back slope exists. The sensor shows the highest performance with the use of yellow light source, which has the highest intensity and the smallest beam divergence. The sensitivity, linear range, resolution and dynamic range of the sensor are obtained at 0.0001 mV/μm, 1500 μm, 70 μm, and 5.0 mm, respectively. The simplicity of the design, high degree of sensitivity, dynamic range and the low cost of the fabrication make it suitable for real field applications.     

反射式光纤位移法检测轧辊磨损度中实用电路的设计

利用反射式光纤位移传感器的工作原理，通过对反射光强信号的检测，提出了一种用于轧辊磨损度在线非接触检测的光电检测法，并重点设计了用于反射式光纤位移法检测轧辊磨损度系统的实用电路。根据轧辊磨损度测量过程的特点及精度要求，阐述和分析了传感器电路系统的原理、组成及性能。理论和实验研究表明，该电路系统工作稳定，精确度和灵敏度均可满足实际要求。此电路系统稍加改进还可适用于类似条件下用反射式光纤位移法进行测量的其他系统。     

Brillouin fiber optic current sensor

A novel reciprocal Brillouin fiber optic current sensor has been developed and tested. The sensor is based on two counter-propagating Brillouin lasers circulating in a fiber ring cavity. It shows a sensitivity of 126 Hz/A that is very close to the maximum sensitivity obtained by using fibers without linear birefringence. The limitations due to the Kerr effect and optical feedbacks in the system are also investigated.     

Theoretical and experimental studies on coupler based fiber optic displacement sensor with concave mirror

A new fiber optic displacement sensor (FODS) is proposed and demonstrated using a multimode fiber coupler as a sensor probe and a concave mirror as a reflective target. A mathematical model is also developed to investigate the performance of proposed FODS at various coupling ratio, fiber diameter, and surrounding media. Three slopes are obtained for the displacement response where the third slope starts at a displacement position of twice the focal length. The numerical results show that higher performance is attained at lower coupler ratio of 50:50 or smaller core diameter. The results also show that the proposed FODS has a potential application in liquid and gas chemical sensors. The experimental performances are also investigated for the proposed sensor where it is observed that the second peak of the displacement curve is located at exactly two times of the focal length or 20 mm.     

二维复用半导体激光器线性调频光纤位移传感器的研究

利用半导体激光器线性调频外差干涉原理和频域多路复用原理,研究了光纤位移传感器多路复用技术,制作了两路复用光纤位移传感器,研究和解决了多路复用时信号串话问题.实验证明,各路之间串话引起的误差小于±0.02μm,每路测量误差小于±0.05μm.     

光纤压力传感器的性能研究

利用自制的全光纤马赫-曾德尔干涉仪,对压力引起的光功率的变化进行了测量和分析,给出了该系统相干检测最佳工作范围是5~13N,灵敏度为-0.130 0μW/N.在不同温度变化范围内,随着压力的增加,光功率分别以0.223 4μW/N到0.482 3μW/N的变化率减小.     

Study of fiber optic sugar sensor

Over the last two decades, the fiber optic technology has passed through many analytical stages. Some commercially available fiber optic sensors, though in a small way, are being used for automation in mechanical and industrial environments. They are also used for instrumentation and controls. In the present work, an intensity-modulated intrinsic fiber optic sugar sensor is presented. This type of sensor, with slight modification, can be used for on-line determination of the concentration of sugar content in sugarcane juice in sugar industry. In the present set-up, a plastic fiber made of polymethylmethacrylate is used. A portion of the cladding (1 cm, 2 cm, 3 cm) at the mid-point along the length of the fiber is removed. This portion is immersed in sugar solution of known concentration and refractive index. At one end of the fiber an 850 nm source is used and at the other end a power meter is connected. By varying the concentration of sugar solution, the output power is noted. These studies are made due to the change in refractive index of the fluid. The device was found to be very sensitive which is free from EMI and shock hazards, stable and repeatable and they can be remotely interfaced with a computer to give on-line measurements and thus become useful for application in sugar industries.     

Statistical and interferometric determination of the optical thickness of a multilayer transparent plate

Optical Review - Wavelength-tuning Fizeau interferometry has been widely used to measure and estimate the optical thickness of optical components. However, in multilayer interferometry, the...     

微纳光纤高温压力传感器

提出了一种基于飞秒激光加工技术制作的微纳光纤高温压力传感器。用飞秒激光在光纤端面加工出法珀腔,制作出的全光纤法珀干涉型压力传感器,从室温到1100℃范围进行了压力温度试验。在不同温度下,压力传感器都有良好的线性输出特性,短时间工作温度超过1100℃,能够满足高温环境下压力测量的需求。     

Ground vibrations detection with fiber optic sensor

In this paper, a fiber optic sensor based on fiber Bragg grating (FBG) is employed to measure the ground vibrations which may be generated by earthquakes, debris flows, landslides, and rock impacts on the ground. The detected vibration signals were analyzed by both fast Fourier transform (FFT) and Gabor transform to obtain the frequency response. The performance of fiber optic sensor was examined and compared with the conventional ground vibration geophone sensor. From the results of field tests, the fiber optic sensor shows highly similarity with conventional geophone sensor for low frequency measurement. The fiber optic vibration sensing system presented in this research is appropriate for sensing ground vibration in the frequency ranges of 10–250 Hz. The sensor proved to be an alternative option for ground vibrations monitoring system.     

一种光纤EFPI高温传感器

提出了一种金属封装的光纤外腔式珐珀(EFPI)高温传感器。利用不同材料的不同热膨胀系数,使EFPI的腔长对温度变化敏感,可以应用在高温场合下。该传感器具有结构简单、灵敏度高、耐高温等特点,测试结果表明,灵敏度为0.3837μm/℃,线性度为0.9956,分辨率为0.26℃。它的正常工作温度范围为0-400℃。     

光纤Sagnac温度传感器

介绍了一种新型的基于光纤Sagnac干涉仪的高精度光纤温度传感器———光纤Sagnac温度传感器。讨论了此传感器的测温原理,推导了被测温度与传感器输出之间的关系,设计并调测了一个具体传感器系统。实验结果表明,此温度传感器具有很高的精度和大的测量范围。     

金属丝杨氏模量的光纤测试方法

采用光纤位移传感器,测量了加载情况下金属丝的微小伸长量,给出了一种杨氏模量的测量方法。理论上, 光纤位移传感器特性,与实验结果进行了对比。通过实验,标定了光纤位多传感器,并测量了不同加载情况下金属丝微小伸长量。采用逐差法处理了实验结果。     

Theoretical analysis of surface plasmon resonance based fiber optic sensor using indium nitride

An extremely sensitive surface plasmon resonance based fiber optic sensor with indium nitride (InN) layer coated on the core of the optical fiber is theoretically analyzed. The proposed sensor exhibits high sensitivity in the near infrared region of spectrum. The optimized value of thickness of InN layer is found to be 70 nm. Possessing high sensitivity of 4493 nm/RIU, the 70 nm thick InN layer based fiber optic SPR sensor illustrates good sensing behavior.     

A simple temperature-insensitive fiber Bragg grating displacement sensor

The study on fiber Bragg grating (FBG) displacement sensor based on monitoring the back-reflected power from an array of novelly embedded FBG sensors is presented. The sensor is a uniform FBG with three sections that are embedded in different layer in a composite lamina. Its bandwidth is displacement dependent and hence its reflected power varies almost linearly with displacement and it is insensitive to temperature variation. Thus, only low-cost photodetector (PD) is required to monitor displacement. This study demonstrates a novel fiber sensor, a method of fabricated the same, and a method to achieve simultaneous multi-sensor measurement.     

反射式光纤位移传感器应用设计实验

基于光的反射原理并结合光纤传感器的特点,设计了反射式光纤位移传感器应用设计性实验.利用反射式光纤传感器测量微小位移的原理,通过测量输出电压与位移的关系确定工作点,测得表面柤糙程度不同的真假钞的输出信号,从而实现对纸币的真假识别.