共查询到20条相似文献,搜索用时 31 毫秒
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Compact fiber optic accelerometer 总被引:1,自引:0,他引:1
A compact fiber optic accelerometer based on a Michelson interferometer is proposed and demonstrated. In the proposed system, the sensing element consists of two single-mode fibers glued together by epoxy, which then act as a simple supported beam. By demodulating the optical phase shift, the acceleration is determined as proportional to the force applied on the central position of the two single-mode fibers. This simple model is able to calculate the sensitivity and the resonant frequency of the compact accelerometer. The experimental results show that the sensitivity and the resonant frequency of the accelerometer are 0.42 rad/g and 600 Hz, respectively. 相似文献
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An experimental demonstration of fiber optic imaging inside a furnace at 1000°C is described, A low-resolution sapphire fiber optic video system was designed, fabricated, and tested for basic performance in a small tube furnace. The imaging fiber bundle was assembled using 100 high-quality sapphire fibers aligned and bonded at each end. Experiments to achieve a high-temperature cladding are described. Reference imaging experiments at room temperature were performed with the sapphire fiber bundle and a commercial glass fiber bundle of comparable sue. Imaging experiments at 1000°C are described and discussed. 相似文献
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基于混凝土模型试验,对涂敷层的传感光纤的裂缝复用能力进行了定量分析,得到了传感光纤和工程结构裂缝夹角在30°,45°,60°时的复用能力与裂缝宽度的关系曲线。对由软性材料构成的光纤涂敷层来说,光纤的复用能力随涂敷层厚度的增加而增大,在与裂缝夹角成45°时,二次涂敷粗光纤的复用能力约为细光纤的5倍,表明光纤敷层对光纤裂缝监测的复用能力具有较大影响。对这种影响的机理进行了理论分析和试验研究,发现当混凝土开裂时,光纤沿混凝土界面的滑移是光纤涂敷层影响光纤裂缝复用能力的主要原因,在光纤与裂缝夹角成45°时,这一影响占60%以上。 相似文献
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Gain band expansion of a Raman amplifier based on a Raman fiber oscillator (RFO) was tested with two Raman lasers, which yielded a broad gain spectrum of about 40 nm. However, they also introduced gain-clamping behavior in the short-wavelength range and abnormal excessive gain in long-wavelength channels, which were undesirable for practical application. The proper mechanism of the behavior was analyzed and experimentally demonstrated to apply to a gain-clamped (GC) amplifier based on a RFO. Appropriate configuration of the GC-RFO for wide gain bandwidth was proposed and characterized. 相似文献
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Maninder Lal Singh 《Optik》2010,121(9):778-782
A novel numerical method has been presented here which is capable of taking into account pulse walk off effect and different data formats such as non return to zero (NRZ), return to zero (RZ) and optical Manchester while evaluating the effect of stimulated Raman scattering (SRS) in dense wavelength division multiplexed (DWDM)-based fiber optic communication systems. Power tilt because of SRS effect in the DWDM systems has been calculated at different data rates and data formats. 相似文献
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Fiber optic hydrophones typically use a long sensor fiber wrapped around an air-filled mandrel to achieve high responsivity. Minimum mandrel diameter is determined by fiber reliability considerations. A miniature hydrophone, with diameter of about a third that of previous hydrophones, is reported. Such a hydrophone has applications for very thin towed arrays. Small diameter fiber with high strength Bragg gratings written through the coating are key enablers. 相似文献
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《Laser \u0026amp; Photonics Reviews》2017,11(1)
The best instrument to measure the refractive index of liquids is the Abbe refractometer which can only provide accuracies of the order of 10−5 at visible wavelengths and 10−4 in the near infrared. Here we present a technique by which the exact wavelength positions in the near infrared frequency comb of a tilted grating inscribed in the core of an optical fiber can be used to measure the absolute value of the refractive index of a liquid in which the fiber is inserted, with an accuracy of ±5×10−5. This is in contrast to typical fiber optic‐based “refractometry” where only refractive index variations can be measured accurately, hence the appellation of “true” fiber optic refractometer here. In addition to the increased accuracy, the fiber refractometer proposed here offers the additional advantages associated with in situ measurements. The performance of this refractometer is demonstrated by measurements in water from room temperature down to near freezing at wavelengths in the 1550 nm window.
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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. 相似文献
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This work is meant to provide a review of different multiplexing topologies employing distributed erbium‐doped fiber and Raman amplification to solve the problem of power‐loss compensation in fiber‐optic sensor (FOS) networks. This is a key parameter in large multiplexing networks, particularly when employing intensity‐modulated sensors. These topologies are studied both theoretically and experimentally, and a comparative analysis is carried out between them. The main parameters considered in the analysis are power budget, optical signal‐to‐noise ratios, scalability and architecture complexity. 相似文献
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A Jayanth Kumar N M Gowri R Venkateswara Raju G Nirmala B S Bellubbi T Radha Krishna 《Pramana》2006,67(2):383-387
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. 相似文献
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High extinction ratio in-fiber polarizers based on 45 degree tilted fiber Bragg gratings 总被引:1,自引:0,他引:1
We report a near-ideal in-fiber polarizer implemented by use of 45 degrees tilted fiber Bragg grating structures that are UV inscribed in hydrogenated Ge-doped fiber. We demonstrate a polarization-extinction ratio of 33 dB over a 100-nm operation range near 1550 nm. We further show an achievement of 99.5% degree of polarization for unpolarized light with these gratings. We also theoretically investigate tilted grating structures based on the Green's function calculation, therein revealing the unique polarization characteristics, which are in excellent agreement with experimental data. 相似文献
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Kazuo Hotate 《Optical Review》1997,4(1):A28-A34
Recent research on future evolution of fiber optic gyros is discussed. Research factors to improve the functions of interferometer
fiber optic gyros in regard to light-source characteristics, temperature change induced drift, and cost reduction are reviewed,
and resonator fiber optic gyros and Brillouin fiber optic gyros are evaluated as next generation configurations. 相似文献
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We report on sensitivity control of fiber optic sensors using microbend long-period fiber gratings. By tuning the phase difference between a pair of periodically aligned rod arrays that sandwiches a single-mode fiber, we can change the coupling strength of the core mode with radiating cladding modes, resulting in variable pressure sensitivity of the transmission power through the fiber. This technique enables control of the measurable range of pressure. When the phase difference is shifted from π toward 0, the measurable range is expanded from 1.7 to 3.3 N/cm and higher using a light-emitting diode as an input light source. 相似文献
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We demonstrate fiber distributed feedback (DFB) lasers using Raman gain in two germanosilicate fibers. Our DFB cavities were 124 mm uniform fiber Bragg gratings with a π phase shift offset from the grating center. Our pump was at 1480 nm and the DFB lasers operated on a single longitudinal mode near 1584 nm. In a commercial Raman gain fiber, the maximum output power, linewidth, and threshold were 150 mW, 7.5 MHz, and 39 W, respectively. In a commercial highly nonlinear fiber, these figures improved to 350 mW, 4 MHz, and 4.3 W, respectively. In both lasers, more than 75% of pump power was transmitted, allowing for the possibility of substantial amplification in subsequent Raman gain fiber. 相似文献
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