共查询到20条相似文献,搜索用时 515 毫秒
1.
2.
3.
正弦锥光纤光栅的数值计算分析 总被引:1,自引:0,他引:1
本文利用耦合模方程对正弦锥光纤光栅的反射谱进行了较为详细的计算和分析,发现,这种光纤光栅的反射谱与普通均匀周期光栅的反射谱有着很大的不同,通过控制光栅锥的形状,可得到类似于梳状滤波器的功能,对这种新型光栅在光纤激光器等方面的应用有指导意义。 相似文献
4.
5.
A taper transition can couple light between a multimode fiber and several single-mode fibers. If the number of single-mode fibers matches the number of spatial modes in the multimode fiber, the transition can have low loss in both directions. This enables the high performance of single-mode fiber devices to be attained in multimode fibers. We report an experimental proof of concept by using photonic crystal fiber techniques to make the transitions, demonstrating a multimode fiber filter with the transmission spectrum of a single-mode fiber grating. 相似文献
6.
An interference-based scheme for fabricating periodic metal gratings on one side of the uniform waist of optical fiber tapers has been developed. Optical characterization of a 5 mm long, 511 nm period gold grating fiber taper with a 10 microm diameter reveals backward coupling to both guided and radiation modes that is explained by using an analytical mode-coupling analysis. A refractometer based on this grating taper has a high and constant sensitivity over a large refractive index operating range of 1 to 1.41. 相似文献
7.
We propose and demonstrate an active Q-switched fiber laser using a high-Q microsphere resonator as the Q-switching element. The laser cavity consists of an Er-doped fiber as the gain medium, a glass microsphere reflector (coupled through a fiber taper) at one end of the cavity, and a fiber Bragg grating reflector at the other end. The reflectivity of the microsphere is modulated by changing the gap between the microsphere and the fiber taper. Active Q switching is realized by oscillating the microsphere in and out of contact with the taper. Using this novel technique, we have obtained giant pulses (maximum peak power approximately 102 W, duration approximately 160 ns) at a low pump-power threshold (approximately 3 mW). 相似文献
8.
9.
基于熔融拉锥技术研制的3 dB宽带耦合器的光纤环形镜的工作原理,提出了一种新型的具有有源闭合腔装置的光纤光栅传感系统。在用作闭合共振腔端镜的环形镜中写入十个波分复用光纤光栅传感元,利用共振腔中接入的法布里-珀罗滤波器,通过控制电压对传感光栅的波长扫描,实现对传感地址的查询。用非平衡的迈克耳孙扫描干涉仪将传感光栅的波长漂移信息变为相移信息,实现传感信号的解调。系统传感灵敏度的实验值为1.5835°/10-6ε,与理论值(1.6662°/10-6ε)基本吻合。 相似文献
10.
11.
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
12.
13.
14.
All-fiber add-drop filters based on microfiber knot resonators 总被引:1,自引:0,他引:1
We demonstrate an all-fiber add-drop filter composed of a microfiber knot (working as a resonator) and a fiber taper (working as a dropping fiber). The dropping taper can be either parallel or perpendicular to the input port of the filter. A quality factor (Q factor) of 13,000 is obtained from a parallel-coupling 308 microm diameter microknot add-drop filter with a free spectral range (FSR) of 1.8 nm. A Q factor of approximately 3300 is obtained from a cross-coupling 65 microm diameter microknot add-drop filter with a FSR of 8.1 nm. This device is particularly easy to fabricate and to connect to fiber systems. 相似文献
15.
光纤光栅传感信号解调技术研究进展 总被引:1,自引:0,他引:1
光纤光栅传感器是一种新型传感器,有着非常广泛的应用前景。限制光纤光栅传感器大量实际应用的主要障碍是传感信号解调,因而,光纤光栅传感信号解调是光纤光栅传感器应用的关键技术之一。本文对现有已报道的光纤光栅传感信号的解调方法进行综述,并归类为:边缘滤波法、匹配滤波法、可调谐滤波法、光源波长可调谐扫描法、射频探测法、光栅啁啾法、CCD分光仪法、干涉法。对各种方法的原理及相关改进方法进行了阐述,并对其优缺点做了比较分析,最后,对光纤光栅传感信号的解调技术发展进行了展望。 相似文献
16.
传统的匹配光纤布拉格光栅型光纤光栅波长解调系统具有波长匹配精度低、调节困难和动态测量范围小的缺点。为了克服上述缺点,采用波长可调谐高斯型滤波器代替传统匹配光纤光栅,提出了一种新型的光纤光栅波长解调技术。建立了基于高斯型滤波器的光纤光栅振动解调系统。对不同频率和振幅的周期性振动进行了解调实验。发现当选择合适带宽的滤波器时,透过滤波器的光功率随压电陶瓷上所加电压信号同步且高保真地变化,表明该系统对振动信号实现了有效的解调。该系统同时具有响应速度快、物理结构简单、动态测量范围大的优点。 相似文献
17.
18.
单模光纤双圆锥体的传输特性 总被引:1,自引:0,他引:1
本文研究并制作了光纤双圆锥体滤波器,给出了耦合模总相位差与滤波性能之间的关系,讨论了推的对称性对滤波器峰值传输的影响,对不同结构的锥体谱特性进行数值计算以验证分析结果,最后给出了实验结果对照. 相似文献
19.
Hirohisa Yokota Takahiro Hasegawa Yoshitaka Satoda Eiichi Sugai Yutaka Sasaki 《Optical Review》1999,6(3):173-179
Fused optical fiber grating couplers (FGCs), in which Bragg gratings are written in the coupling regions of fused optical fiber couplers with tapered shapes along them are theoretically and experimentally investigated. By coupled mode analysis considering these tapered shapes, the drop efficiencies of the FGCs, which are inherently zero for the normal fiber couplers without grating, are calculated. The grating offset, which is the difference between the centers of grating and the coupler taper, is found to be effective to increase the drop efficiency of the FGC. It is determined that the tapered shapes influence the wavelength dependence of the drop efficiency and tolerate the grating offset precision. Apodizations for the grating of FGC are found to be effective in suppressing side lobes of the drop efficiency. Measurement of the wavelength characteristics of drop efficiency and the temperature characteristics of drop wavelength of the fabricated fused FGC confirm that the lightwave with specific wavelength can be dropped by the FGC and that the temperature dependence of the drop wavelength is similar to that of Bragg wavelength changes of usual fiber Bragg gratings. 相似文献
20.
A novel optical recirculating filter for RF applications is described, which exploits a specially designed fiber grating with a ramped spectral profile to enable optimization of the filter response. The design overcomes the limitations imposed by loss in conventional fiber recirculating filters. Additionally, a tunable free spectral range is demonstrated by using the device in a grating array. Both theoretical and experimental results are presented and discussed. 相似文献