共查询到20条相似文献,搜索用时 15 毫秒
1.
We demonstrated a fiber sensing system using the method of wavelength locking of two identical fibers Bragg gratings (FBG) to interrogate the wavelength shift by directly measuring the intensity of the reflection from the sensing Bragg grating. The light source of the fiber sensing system is an EDFA fiber ring laser pumped by a 980 nm laser diode and a narrow bandwidth fiber Bragg grating for the filter of the ring laser resonator. The wavelength shift is converted to the intensity deviation of the reflection from the sensing FBG under strain variation, and is able to achieve real-time sensing of the dynamic strain sensing in civil engineering. The characteristics and key factors to maintain stability of the dynamic strain sensing system are discussed. 相似文献
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J. A. Alvarez-Chavez A. Martínez-Rios I. Torres-Gomez A. Gonzalez-Garcia H. L. Offerhaus 《Laser Physics》2008,18(3):353-356
We report on a wide wavelength tuning in a double-clad ytterbium-doped fiber laser. The laser cavity consists of an array of broadband high-reflection fiber Bragg gratings and a bulk grating as the output coupler and wavelength selection element. The proposed fiber laser configuration combines a low intracavity loss of the fiber Bragg grating mirrors with a wide wavelength tuning of the bulk gratings. We demonstrate a >70-nm wavelength tuning range, limited only by the available fiber Bragg gratings. 相似文献
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S. R. Abdullina S. A. Babin A. A. Vlasov S. I. Kablukov 《Optics and Spectroscopy》2007,103(6):1007-1011
A tuning method of a fiber Bragg grating by the bending compression-tension is considered. With this method, a relative tuning range of the resonance wavelength of the grating of about 5% has been obtained. The changes in the shape of the spectrum and in the grating reflectivity during the tuning process are studied. The reflectivity of the fiber Bragg grating has been found to considerably increase with increasing degree of compression. It is shown that such an increase is caused by compression-induced changes in the refractive index modulation amplitude in the grating. The fiber Bragg grating developed has been applied for tuning the radiation wavelength of an ytterbium fiber laser. The tuning range of the laser has been found to be 45 nm around the central wavelength 1080 nm. 相似文献
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Jianliang Yang Yunqi Liu Sweechuan Tjin Jianping Yao 《International Journal of Infrared and Millimeter Waves》2002,23(8):1241-1250
A photonics true-time-delay system for phased array antenna beam steering employing a novel tunable chirped fiber grating delay line and a multi-wavelength erbium-doped fiber ring laser source based on a sampled grating filter is proposed. The tunable chirped fiber grating, which act as a continuous time-delay element, is achieved by bending a uniform fiber Bragg grating bonded at a slant onto the lateral surface of a simply supported beam. This technique allows the dynamic control of the chirp rate and spectral width of the grating without center wavelength shift. By adjusting the chirp rate of the fiber grating via bend strain, this kind of tunable chirped fiber grating could achieve very low and adjustable delay times, therefore provides higher angle resolution for scanning microwave beam, even the wavelengths of laser source are fixed and un-tunable. The true-time-delay system using proposed tunable chirped fiber grating delay element and sampled grating based laser source is constructed and demonstrated experimentally. 相似文献
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分析了一种有源型光纤水听器的水声传感原理,在一段掺铒光纤中写入具有π相移的光纤光栅构成光纤激光器,水声压力作用在激光器上引起激光波长的移位,采用干涉法检测出波长移位引起的相位变化即得到声压的信息.水声探测实验表明,有源型光纤水听器的声压灵敏度为-166.5 dB(参考值1 rad/μPa).将不同工作波长的四元光纤水听器串接于一根光纤内组成水听器阵列,使用带通波分复用器将阵列发出的激光分离至各独立通道后检测出相应的声压信号,测得水听器之间的级串扰小于-60 dB,且单元水听器水声响应的动态范围不受影响. 相似文献
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光纤光栅梳状滤波器及其在新型可选波长激光器中的应用 总被引:4,自引:0,他引:4
对现有在同~段光纤上多次写入光栅制成光栅梳状滤波器的方法进行了改进,利用增加光栅长度,精确控制不同光栅的曝光时间,并结合调整光栅实际写入长度的方法,制成了不均衡度小于5%、最低峰值反射率高于95%的光纤光栅梳状滤波器;同时提出了一种新颖的可选波长光纤激光器结构。采用由上述方法制作出的反射率均衡的光纤光栅梳状滤波器和可调光滤波器结合在一起进行波长选择,实现了波长的快速准确选择,同时各个波长激光的输出特性稳定,功率均衡性好,边模抑制比大于50dB。 相似文献
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基于虚拟仪器和可调谐激光技术的光纤光栅传感系统 总被引:4,自引:3,他引:1
提出了一种新颖的基于虚拟仪器(VI)和可调谐激光技术的光纤光栅(FBG)传感系统,利用可调谐激光对由光纤光栅组成的传感器阵列进行波长扫描,实现了多根光栅的复用准静态解调,并结合抖动技术和反馈环结构,使得探测信号在每一根传感光栅中心波长处过零,以提高系统在测定波长偏移时的分辨力。当反馈环工作在闭环状态下时,该系统还可对单根光栅实现动态跟踪锁定,实现单根光栅的动态解调。该传感系统的数据采集采用虚拟仪器技术,通过多通道同时输入输出实现了在线实时解调。实验采用了4根光栅组成传感阵列,获得了静态多根光栅小于1με和单根光栅动态频率10 Hz时3.3 n/εHz的解调分辨力,动态应变范围在850με。 相似文献
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Highly reliable strain-tuning of an Erbium-doped fiber laser for the interrogation of multiplexed Bragg grating sensors 总被引:1,自引:0,他引:1
Aleksander S. Paterno Nilton Haramoni Jean C.C. Silva Hypolito J. Kalinowski 《Optics Communications》2007,273(1):187-192
The authors implemented a tunable linear cavity Erbium-doped fiber (EDF) laser for the interrogation of multiplexed fiber Bragg grating sensors (BGS). A high-strength single-pulse draw-tower fiber Bragg grating (FBG) was used as the mechanically tunable element enabling the rapid wavelength sweeping of the laser center wavelength. A simple algorithm to process the noisy acquired data and identify the peak of the BGS spectra was employed. For the first time, this type of configuration was used to reliably interrogate at least three fiber Bragg grating sensors with a standard wavelength spacing between the Bragg wavelengths of 3 nm, without risk of breaking the stretched fiber, using an FBG with a simple PZT driven mount as the tuning elements. 相似文献
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A single-mode fiber laser based on an intracavity core-cladding mode conversion is demonstrated. The fiber laser consists of an Er-doped active fiber and two fiber Bragg gratings. One Bragg grating is a core-cladding mode converter, and the other Bragg grating is a narrowband high reflector that selects the lasing wavelength. Coupling a single core mode and a single cladding mode by the grating mode converter, the laser operates as a hybrid single-mode laser. This approach for designing a laser cavity provides a much larger mode area than conventional large-mode-area step-index fibers. 相似文献
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We demonstrate a wavelength-tunable, passively mode-locked erbium-doped fiber laser based on graphene and chirped fiber Bragg grating. The saturable absorber used to enable passive mode-locking in the fiber laser is a section of microfiber covered by graphene film, which allows light-graphene interaction via the evanescent field of the microfiber. The wavelength of the laser can be continuously tuned by adjusting the chirped fiber Bragg grating, while maintaining mode-locking stability. Such a system has high potential in tuning the mode-locked laser pulses across a wide wavelength range. 相似文献
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A novel configuration of the tunable fiber laser with uniform wavelength spacing in dense wavelength division multiplexing (DWDM) application is proposed. The ring type tunable fiber laser consists of an all-fiber comb filter which determines the wavelength spacing, and a piece of adjustable fiber grating to select the discrete lasing wavelength for WDM application. The proposed all-fiber ring type tunable laser has potential application in the DWDM and other optical systems due to its advantages such as narrow linewidth, easy tuning, uniform wavelength interval, etc.. 相似文献
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一种测定光纤光栅布拉格反射波长位移的简单方法 总被引:3,自引:0,他引:3
报道一种简单的光纤光栅对参考法测定光纤光栅布拉格波长的位移的方法,其原理是利用一个布拉格波长可调谐的光纤光栅去跟踪另一个光纤光栅拉格波长的变化,测得的光栅布拉格波长的温度灵敏度为0.0088nm/℃,这和用可调谐半导体激光器测得的结果十分接近。 相似文献
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Highly sensitive dynamic strain measurements by locking lasers to fiber Bragg gratings 总被引:1,自引:0,他引:1
A novel, sensitive, simple, and robust strain interrogation technique is analyzed and experimentally tested. By locking a laser wavelength to the midreflection wavelength of a standard fiber Bragg grating and measuring the error signal, we achieve high dynamic strain sensitivity of 45 picostrain/ radicalHz rms at 3 kHz, where the dominant noise in the experiment is the laser frequency noise. 相似文献
18.
Gilberto Anzueto-Sánchez Alejandro Martínez-Rios Ismael Tores-Gómez Daniel Ceballos-Herrera Romeo Selvas-Aguilar Victor Duran-Ramirez 《Optical Review》2007,14(2):75-77
We describe a tunable double-clad Yb-doped fiber laser based on a long period fiber grating mechanically induced in a section
of single mode holey fiber inserted into the laser cavity. The mechanically induced long period holey fiber grating acts as
a wavelength-selective fiber filter whose central wavelength, linewidth, and strength can be tuned by changing the period,
the length of the grating, and the applied pressure. The fiber laser gives a ∼12.6 nm tuning range, from ∼1079:4–1092nm, with
slope efficiencies of 18.7–26.3% at this wavelength range, with respect to the launched pump power. 相似文献
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We reported a wavelength-flexible all-polarization-maintaining self-sweeping fiber laser based on the intracavity loss tuning brought by the bent optical fiber. The bidirectional cavity structure achieved the self-sweeping effect due to the appearance of the dynamic grating in the active fiber with the spatial hole burning effect. Under this, a section of fiber was bent into a circle for adjusting the loss of the cavity. With a descending diameter of bent fiber circle, the sweeping range moves to the shorter wavelength and covers a wide range from 1055.6 to 1034.6 nm eventually. Both the initial wavelength of self-sweeping regime and the threshold of the fiber laser show exponential correlation with the diameter of the circular fiber. Our work provides a compact and low-cost way to achieve the broad wavelength-flexible self-sweeping operation. 相似文献