共查询到20条相似文献,搜索用时 31 毫秒
1.
J. M. Estudillo-Ayala J. Ruiz-Pinales R. Rojas-Laguna J. A. Andrade-Lucio O. G. Ibarra-Manzano E. Alvarado-M ndez M. Torres-Cisneros B. Ibarra-Escamilla E. A. Kuzin 《Optics and Lasers in Engineering》2003,39(5-6):635-643
The fiber Sagnac interferometer of low birefringence and twist is analyzed numerically in the linear region. A novel method for measurement of the birefringence of the fiber and the angle of rotation of the axes inside the fiber loop of the interferometer is also presented. 相似文献
2.
通过引入椭圆掺锗芯和侧向泄露通道, 提出并研制出一种侧漏型光子晶体光纤(photonic crystal fiber, PCF). 应用结构重构全矢量有限元数值分析法分析了设计结构和实际研制的侧漏型PCF的传输特性. 研制的侧漏型PCF, 在波长1550 nm处基模的平均模场直径为9.275 μm, 与G652标准单模光纤具有很好的适配性, 模式双折射为0.837× 10-4, 群双折射约为1.508× 10-4. 基于研制的侧漏型PCF光纤构建了Sagnac干涉仪, 对其群双折射进行了测量. 测量结果表明:当侧漏型PCF光纤达到一定长度时, 在1450–1750 nm波长范围内, 二阶模在光纤中不能成为有效传输模式, 光纤可以实现单模传输; 另外, 研制的侧漏型PCF群双折射实验的测量平均值, 与数值分析结果相符合. 侧向泄露通道的引入, 增强了侧漏型PCF光纤对外界参量变化的敏感性, 提高了其在扭转、弯曲、压力等参量的光纤传感和高性能光纤激光器构建等方面的应用潜能.
关键词:
光子晶体光纤
侧向泄露通道
双折射
Sagnac干涉仪 相似文献
3.
4.
A sensing system for micro-displacement measurement based in a suspended-core fiber Sagnac interferometer is presented. The suspended-core fiber characterization was made through the use of an optical backscatter reflectometer, screening its multimodal and birefringent behavior. Its sensitivity to displacement measurements is shown to be due only to birefringence, being that core-cladding mode coupling is negligible. High precision (~0.45 μm) was obtained using three different measurement instruments, showing an extremely high stability and high insensitivity to temperature, demonstrating that the sensing system has the ability for low cost applications. 相似文献
5.
6.
Non-contact detection of laser-generated surface acoustic waves using fiber optic Sagnac interferometer 总被引:1,自引:0,他引:1
A high powered Q-switched Nd:YAG laser was used to excite the surface waves, and an optical fiber sensor was used to detect the out-of-plane displacements due to the propagating waves. This sensor is based on the fiber optic Sagnac interferometer, which has the path-matched configuration and does not require active stabilization. Quadrature phase bias between two interfering laser beams in the Sagnac loop is applied by controlling the birefringence in an optical path using a fiber polarization controller. A stable quadrature phase bias can be confirmed by observing the interferometer output according to the change of phase bias. Additional signal processing is not needed for the detection of ultrasonic waves using the Sagnac interferometer. The performance of the fiber optic Sagnac interferometer was investigated, and laser-generated surface wave signals were detected using this fiber optic sensor. The developed fiber optic sensor configured in this study is very simple and is effective for non-contact detection of ultrasonic waves. 相似文献
7.
A magneto-optic modulator with a magnetic fluid film inserted into an optical fiber Sagnac interferometer is proposed. The magnetic fluid exhibits variable birefringence and Faraday effect under external magnetic field that will lead to a phase difference and polarization state rotation in the Sagnac interferometer. As a result, the intensity of the output light is modulated under the external magnetic field. Moreover, the modulator has a high extinction ratio and can easily be integrated in a single-mode fiber system. The performance of the modulator is not affected by ambient temperature variation from room temperature to 40 °C. 相似文献
8.
9.
Analysis of a second-order polarization-independent filter made of a single ring resonator and a Sagnac interferometer 总被引:1,自引:0,他引:1
Fufei Pang Feng Liu Xiuyou Han Haiwen Cai Ronghui Qu Zujie Fang 《Optics Communications》2006,260(2):567-570
A novel second-order polarization-independent filter made of a single ring resonator and a Sagnac interferometer (SRRSI) is proposed, and its filtering characteristics are investigated. By using birefringence in waveguide, a single ring resonator can be used to synthesize a filter with second-order response. Analytical formulas are derived for characteristics of the SRRSI varied with waveguide parameters, such as the coupling coefficient; and the critical condition of a second-order Butterworth filter is given. The influence of loss in the ring resonator is also analyzed. 相似文献
10.
提出了一种基于光子晶体光纤Sagnac干涉仪的横向压力传感器。使用的光子晶体光纤为低双折射光纤,首先预先在Saganc环中的光子晶体光纤上施加初始压力,使Sagnac干涉仪产生正弦干涉光谱,然后再将被测物体放在光子晶体光纤上,由于被测物体重力的作用,Saganc干涉仪输出的光谱产生移动,实现横向压力传感测量。传感器具有高灵敏度0.529 nm/(N·mm)及超低的温度系数-0.4 pm/℃,其环境温度的影响可以忽略。 相似文献
11.
基于Sagnac原理的单轴分布式光纤传感系统偏振态分析 总被引:9,自引:8,他引:1
针对Sagnac干涉型单轴分布式光纤传感器中使用单模光纤作为传感器件时,由于传输光偏振态在双折射影响下所带来的干涉信号“偏振诱导衰落”问题,运用琼斯矩阵分析法,建立了该型传感器系统在传感光纤双折射和外部事件共同作用下,传输光的偏振态对系统功率传输系数影响的数学模型;仿真分析了在传感光纤线性双折射和圆双折射共同作用下,传输光的偏振态对系统功率传输系数的影响;提出了使用法拉第旋转镜提高系统抗偏振能力的改进方法.仿真结果表明,该方法能很好地消除光纤线性双折射和圆双折射. 相似文献
12.
Y.-G. Han 《Applied physics. B, Lasers and optics》2009,95(2):383-387
We propose a novel and simple scheme for a temperature-insensitive strain measurement by using a birefringent interferometer
configured by a polarization-maintaining photonic crystal fiber (PM-PCF). The wavelength-dependent periodic transmission in
a birefringent interferometer can be achieved by using a PM-PCF between two linear polarizers. Since the PM-PCF is composed
of a single material, such as silica, the peak wavelength shift with temperature variation can be negligible because of the
small amount of the birefringence change of the PM-PCF with temperature change. The measured temperature sensitivity is −0.3 pm/°C.
However, the peak wavelength can be changed by strain because the peak wavelength shift is directly proportion to strain change.
The strain sensitivity is measured to be 1.3 pm/με in a strain range from 0 to 1600 με. The measurement resolution of the
strain is estimated to be 2.1 με. The proposed scheme has advantages of simple structure and low loss without a Sagnac loop,
temperature insensitivity, ease installation, and short length of a sensing probe compared with a conventional PMF-based Sagnac
loop interferometer. 相似文献
13.
We describe a polarization Sagnac interferometer with an in-loop half-wave plate that allows signal detection at the reciprocal port of the beam splitter while maintaining the ability to detect the signal at a dark fringe. Postmodulation and balanced heterodyne detection are used to recover the signal. This topology is simple to control because of its common-path characteristics and its collinear signal and local oscillator. The robustness of this scheme to amplitude and frequency fluctuations of the laser is demonstrated. Intraloop birefringence in this interferometer acts as a loss, reducing the power on the detector. The magnitude of this loss is discussed and experimentally verified. 相似文献
14.
A new type of all-fibre Sagnac interferometer composed of two loops
is proposed and analysed in detail. It can be used with a very long
transmission line while maintaining excellent performance
characteristics due to the automatic compensation of any
birefringence effects in the trunk fibre. Preliminary experiments at
1310~nm wavelength with a 70~km long trunk fibre demonstrated an
interference visibility as high as 98%, indicating that this
scheme has promising potential applications. 相似文献
15.
O. Pottiez Author Vitae B. Ibarra-Escamilla Author Vitae Author Vitae R. Grajales-Coutiño Author Vitae Author Vitae 《Optics & Laser Technology》2010,42(2):403-408
In this paper we study theoretically and experimentally a wavelength-tuneable Sagnac birefringence filter. The device is a Sagnac interferometer including a symmetric fibre coupler and a length of high-birefringence fibre in the loop. A wave retarder is inserted at each end of the birefringent fibre for absolute wavelength tuning. We show theoretically that wavelength tuning through wave plate orientation ensuring constant amplitude of the filtering function is possible only if a minimum of two wave retarders are included in the setup. The position of the transmission peaks then varies linearly with the angle of one of the retarders and can be adjusted over one entire channel spacing. This happens only when a quarter-wave retarder and a half-wave retarder are used, if the former is oriented at 45° with respect to the fibre birefringence axes, while the orientation of the latter serves as the adjustment parameter. The theoretical predictions are confirmed by the experimental results. 相似文献
16.
A novel configuration for measuring femtosecond polarization mode dispersion (PMD) with a pi-shifted Sagnac interferometer is studied. The advantages of this configuration include a response that is independent of the orientation of the device under test. This independence allows characterization of the first-and second-order PMD by measurement of the wavelength dependence of the differential group delay and of the orientation of the device's principal states of polarization. The method provides an extension of the dynamic range of the Sagnac interferometer technique to few-femtosecond PMD measurement. 相似文献
17.
We present a theoretical and experimental investigation of a Sagnac interferometer incorporating a fiber optic recirculating-ring delay line with an erbium-doped fiber amplifier to increase the effective length of the Sagnac loop and thereby improve the low-frequency response. Theoretical calculations show that the low-frequency response of the interferometer is enhanced as expected. However, the noise penalty of using a fiber amplifier in the ring is quite high, especially at low frequencies. The signal-to-noise ratio at low frequencies, using a superfluorescent erbium fiber source, is demonstrated as increasing by a factor of 2 compared to a single-loop Sagnac interferometer with the same total length of fiber, but without fiber amplifier. 相似文献
18.
An analysis is made of the conditions under which the coupling of orthogonal polarization modes at random inhomogeneities
in single-mode optical fibers leads to an increase in the correlation length of a source of nonmonochromatic radiation. It
is shown that when long-base fiber ring interferometers with a single-mode fiber ring system possessing weak linear birefringence
are used, the correlation length of the nonmonochromatic radiation at the interferometer exit is increased, which means that
the interference pattern can have satisfactory visibility even when there is an appreciable difference between the interferometer
arms as a result of the Sagnac effect due to the Earth’s rotation. The calculations were made by mathematical modeling of
random inhomogeneities in the fiber.
Zh. Tekh. Fiz. 69, 140–143 (July 1999) 相似文献
19.
An optical fiber twist sensor based on Sagnac single-mode optic fiber interferometer is proposed. The stress-induced birefringence of single-mode optical fiber is obtained by applying a transverse force against a short length of singlemode fiber. A high sensitivity and resolution of the twist angle measurement of 0.19 nm/° and 0.002° is achieved experimentally, respectively. The proposed sensor is more convenient and simple than that of standard polarization-maintaining fibers. 相似文献
20.
We describe a novel feedback interferometer for real-time, unambiguous measurement of surface profiles that consists of a polarization Sagnac interferometer and an optically addressed phase-only spatial light modulator. In this system the output intensity from the Sagnac interferometer is optically fed back to the phase modulator placed in one arm of the interferometer, which produces a sawtooth fringe intensity profile (instead of the conventional cosinusoidal one) that is directly and unambiguously related to the surface profile. Preliminary experimental results demonstrate the feasibility of applying this system to surface-profile measurement. 相似文献