A 2 by 2 wavelength tunable Fabry-Perot filter by using an electro-optic polymer film

A tunable Fabry-Perot (F-P) filter by using electro-optic polymer film is proposed. The electro-optic polymer is alkoxysilane dye (ASD)/SiO2-TiO2 hybrid material, whose electro-optic coefficient γ33 is about 5 pm/V. The wavelength tuning range of 3.8 nm under 400-V DC voltage and the nonlinear characteristic with the electric field have been obtained via electro-optical properties of polymer. Both of polymer film fabrication and F-P filter design have been introduced. The tunable F-P filter is designed for the application of two-input/two-output port wavelength-selective optical switch. Also, some problems have been discussed in this letter.     

分布式光纤布拉格光栅解调系统

提出并实现了一种可满足工程实用要求的分布式光纤布拉格光栅解调系统。该系统通过可调谐光纤F-P滤波器的连续扫描实现波长信号的解调。该传感系统扫描带宽50nm,单点工作带宽5nm,对一股应用系统每根单纤可设20∽30个点,分辨力5pm。     

基于扫描光纤激光器的光纤传感解调仪研究

介绍了一种基于扫描光纤激光器的光纤传感解调系统.采用氰化氢（HCN）气体吸收池作为波长参考基准,采用三次多项式拟合的方法来确定光纤F- P可调谐滤波器的波长与驱动电压的对应关系,可调谐滤波器扫描过程中对扫描电压、多路光谱信号进行同步采样,实时标定.实验结果表明,该解调系统在1 510 nm到1 590 nm波长范围内对FBG反射峰值波长的分辨率为1.4 pm,长期波长重复性达到3.2 pm.利用该系统实现了对FBG反射峰值波长和光纤EFPI传感器腔长的高准确度解调.     

Widely ultra-narrow linewidth 104 nm tunable all-fiber compact erbium-doped ring laser

A widely tunable narrow linewidth compact erbium-doped all-fiber ring laser with 104 nm tuning range was reported. An all-fiber Fabry-Perot filter (FFP-TF) was used to realize the laser tuning output, and the wavelength at constant voltage had high time stability. With the 8 m length erbium-doped fiber as gain medium, we realized widely tunable laser from 1513 to 1617 nm with the linewidth less than 40 pm at any wavelength. Pumped by the 976 nm laser diode, the fiber laser worked with slope efficiency of above 10% and threshold of less than 21 mW.     

电压调谐液晶滤光片的研究

对以液晶为腔内物质的液晶法布里珀罗调谐滤光片进行了改进 ,在原来法布里珀罗腔的两侧各加一偏振镜 ,使两个偏振镜的起偏方向平行 ,并且偏振方向都相对于液晶分子长轴的方向成 45°角 ,入射光经多光束干涉后再经偏光干涉 ,导出其透射峰满足的条件为 2 (n∥ -n⊥)Lcosθ =mλ ,这样便克服了原有调谐滤光片两套光谱难以区分的缺点。对改进后的滤光片进行测试 ,在 15 5 0nm附近对该电调谐滤光片的滤光特性做了细致的分析     

TUNABLE FIBER FABRY-PEROT FILTER FOR OPTICAL CARRIER-SUPPRESSION AND SINGLE-SIDEBAND MODULATION IN RADIO OVER FIBER LINKS

A novel method of simultaneous realization of optical carrier-suppression and single-sideband modulation using fiber Fabry-Perot tunable filter is presented. In order to enhance transmission performance of radio over fiber links, we use a fiber Fabry-Perot tunable filter to filter out one sideband as well as suppress the optical carrier power. The results demonstrate 20.5dB and 14.2dB improvement in the signal noise ratios when 18GHz and 10GHz microwave signals carrying 5Mbit/s quadrature-phase-shift-keyed (QPSK) format data is transmitted over 35 km single mode fiber, respectively.     

一种用于密集波分复用系统中的可调谐液晶法布里-珀罗滤光片

基于液晶分子的双折射特性，设计并制作了一种结构简单的可用于波分复用系统中的可调谐液晶法布里-珀罗滤光片。对器件的光谱调谐特性进行了分析和模拟，并得到了液晶分子的折射率调制与其分子在电场作用下产生的转动角度之间的关系式。最后，对所设计的结构进行了制作和实验，测试结果显示了滤光片的性能受液晶分子的排列特性和法布里-珀罗腔的反射镜参量的影响较大，同时实验表明了这种利用向列型液晶分子作为法布里-珀罗腔内介质的可调谐滤光片在加电压调试下其调谐性能良好，调谐范围可覆盖C波段，透过峰的半峰全宽达到了0．8nm，实验结果与设计相吻合。     

Tunable-optical-filter-based white-light interferometry for sensing

We describe tunable-optical-filter-based white-light interferometry for sensor interrogation. By introducing a tunable optical filter into a white-light interferometry system, one can interrogate an interferometer with either quadrature demodulation or spectral-domain detection at low cost. To demonstrate the feasibility of effectively demodulating various types of interferometric sensor, experiments have been performed using an extrinsic Fabry-Perot tunable filter to interrogate two extrinsic Fabry-Perot interferometric temperature sensors and a diaphragm-based pressure sensor.     

一种新型可调谐红外滤光片的设计和应用

可调谐红外滤光片是高分辨率红外成像仪谱段识别和分光的重要光学器件.本文介绍了一种新型可调红外滤光片———液晶法布里-珀罗滤光片的基本原理、设计参数、制作方法,分析了这种滤光片的透射光谱、精细度、带宽、镜面反射率和腔长之间的关系,以及外加电压和温度对透射波长的影响,给出了消除偏振效应的几种方案.并对液晶法布里-珀罗滤光片在空间遥感,特别是红外探测方面的应用前景进行了展望.     

Free-spectral range tunable Fabry-Perot filter with superimposed fiber Bragg gratings

A novel free-spectral range (FSR) tunable Fabry-Perot filter (FPF) with two superimposed fiber Bragg gratings (SFBGs) is proposed and experimentally demonstrated. The SFBGs, initially uniform in period with slightly different Bragg wavelengths, were glued onto the lateral surface of a specially-designed cantilever beam and linearly chirped by beam bending-induced strain gradient. As a result, their reflection bands overlap and a grating-based FPF with a tunable FSR is formed. A continuously tunable FSR of 0.1-0.5 nm has been achieved in the experiment.     

高速大容量光纤光栅解调仪的研究

采用半导体光放大器和可调谐法布里-珀罗滤波器,以环路结构组成高速扫描激光器,结合光耦合器、光环路器和光电二极管等,形成4通道大容量高速光纤光栅解调仪。系统采用2kHz的类三角波调制信号,驱动法布里-珀罗滤波器在50nm的光谱范围内进行快速扫描。通过引入光纤梳状滤波器和单峰滤波器组成的参考通路,消除法布里-珀罗滤波器的非线性效应和扫描波长漂移问题,使得解调仪具有很好的稳定性和线性度。高速光纤光栅解调仪的稳定性为2pm,分辨率为1pm,线性度为0.99957,测量精度为5pm,解调频率为2kHz。     

Robust tunable single-frequency operation of a diode laser by a self-pumped phase-conjugate reflector and a high-finesse filter

A novel form of extended-cavity diode laser attains robust tunable single-frequency operation with narrow linewidth. The laser cavity includes a self-pumped photorefractive phase-conjugate reflector for wavelength-adaptive narrowband feedback and a compact high-finesse tunable intracavity ring filter for single-longitudinal-mode selectivity and control. Its performance around 830 nm is verified with a simple Fabry-Perot laser diode and by Doppler-free two-photon spectroscopy in atomic cesium.     

Tunable wavelength filtr in extrinsic fabry-perot of optical fiber

Characteristics of a tunable wavelength filter in extrinsic Fabry-Perot of optical fiber are studied both theoretically and experimentally in this paper. Using a slabby PZT-51, a tuning range of over 10nm is achieved by changing the distance between two fiber end faces. We chose a SLED to provide incident light into the filter and achieved a filter with narrow passband(subnanometer bandwidth). The basic characteristics of the filter, as well as the special properties of its output spectrum, are discussed and analyzed.     

Tunable Single-Passband Microwave Photonic Filter Based on Sagnac Loop and Fabry-Perot Laser Diode

A tunable single-passband microwave photonic filter is proposed and demonstrated, based on a laser diode(LD)array with multiple optical carriers and a Fabry-Perot(F-P) laser diode. Multiple optical carriers in conjunction with the F-P LD will realize a filter with multiple passbands. By adjusting the wavelengths of the multiple optical carriers, multiple passbands are merged into a single passband with a broadened bandwidth. By varying the number of the optical carrier, the bandwidth can be adjusted. The central frequency can be tuned by adjusting the wavelength of the multiple optical carriers simultaneously. A single-passband filter implemented by two optical carriers is experimentally demonstrated.     

可调谐液晶法-珀滤光片的研究

提出了一种可用于密集波分复用系统中的新型可调谐滤光片的设计方法,该设计利用了液晶的双折射现象,以及液晶盒内法-珀效应,从理论上分析了器件的光谱特性,计算了液晶分子的折射率调制和其分子转动角度的关系.并对器件进行了性能测试.实验结果与理论吻合较好.     

All-fiber widely wavelength-tunable thulium-doped fiber ring laser incorporating a Fabry-Perot filter

We demonstrate 1940 to 2010 nm continuous CW wavelength-tuning in a thulium-doped fiber laser (TDFL), using only fiber-format components. A fiber Fabry-Perot (FP) tunable filter is employed to achieve the wavelength tunability of 70 nm. By imposing a 200 Hz triangle wave signal on the filter, rapid wavelength-sweeping is demonstrated from 1952 to 1992 nm every 5 ms, corresponding to 8 nm/ms. This all-fiber wavelength-tunable and swept laser may find applications such as gas monitoring in the wavelength region of 2 μm.     

基于法布里-珀罗调谐滤波器的傅里叶域锁模扫频激光光源

报道了一个光纤型1300 nm波段的傅里叶域锁模(Fourier domain mode locking, FDML)扫频激光光源, 用于扫频光学相干层析成像技术 (optical coherence tomography, OCT) 成像. 本实验扫频激光光源采用包含增益介质、调谐滤波器和延迟线组成的长腔激光谐振腔以及光功率增强单元. FDML扫频激光光源具有快速和高度稳定运转模式, 相位稳定性好. 基于法布里-珀罗调谐滤波器(fiber Fabry-Perot tunable filter, FFP-TF)的FDML扫频激光光源扫频范围为130 nm, 半高全宽为70 nm, 输出平均功率是11 mW. 与基于FFP-TF的短腔的扫频光源做了对比研究, FDML扫频光源速度从短腔的8 kHz提高到了48.12 kHz, 对应生物组织OCT成像轴向分辨率为7.8 μm, 比短腔的减小了1.9 μm. 关键词： 光学相干层析技术 扫频激光光源 傅里叶域锁模 法布里-珀罗调谐滤波器     

Compact interrogator for fiber optic Bragg sensors based on an acousto-optic filter formed by photonic crystal rows of air holes

Fiber optic sensors are typically used with expensive tunable lasers or optical spectrum analyzers for wavelength interrogation. We propose to replace the tunable laser by a broadband optical source incorporated with a novel thin linewidth acousto-optic tunable filter. It utilizes optical beam expanders constituted by photonic crystal rows of air holes in LiNbO(3) waveguide. A new design is numerically studied for a short structure (with 32 photonic crystal rows) by a two-dimensional finite-difference time-domain method. Extrapolation of these results to larger structure sizes (about 1 cm) demonstrates the possibility to develop compact interrogators with 0.4 pm wavelength resolution and 40 nm tunable range around 1550 nm.     

Single-longitudinal-mode erbium-doped fiber laser based on a fiber Bragg grating Fabry-Perot filter

A novel single-longitudinal-mode (SLM) erbium-doped fiber laser with a simple linear cavity based on a fiber Bragg grating Fabry-Perot filter (FBG-FPF) and a narrowband (～0.06 nm) FBG is proposed and demonstrated experimentally. Two uniform FBGs form the FBG-FPF, which has two ultranarrow transmission bands with a bandwidth of 0.12 pm and a wavelength spacing of 0.095 nm. By slightly tuning the central wavelength of the narrowband FBG, SLM lasing at 1549.658 or 1549.563 nm (corresponding to the two transmission peaks of the FBG-FPF) is achieved with a laser output power of ～4 mW, when the pump power is ～75 mW.     

基于金属-电介质-金属波导结构的等离子体滤波器的数值研究

基于金属-电介质-金属波导结构, 提出了一种含双侧多支节型等离子波导滤波器, 采用有限元法研究了其透射特性. 在该结构的透射谱中观察到了基于电磁诱导透明效应的四个窄带透射峰, 并通过模场分布有效阐释了透射谱线中峰值、谷值的产生的物理机理. 数值研究同时表明当每个支节长度线性增加时, 透射峰中心波长也将线性增加. 这一结果可用于指导可调谐、多通道窄带滤波器的设计.