全光纤声光可调谐滤波器声信号调理电路设计

声波信号的质量对于全光纤声光可调谐滤波器的滤波稳定性及调谐范围等都起着重要作用.该文设计制作的声信号调理电路有效满足了全光纤声光可调谐滤波器对声波信号频率、幅度、失真度等参数的要求.将该电路应用于光纤光栅声光可调谐滤波器的声信号控制实验中,实现了输出波长在声波信号控制下快速、稳定的连续调谐.     

DWDM系统中的光滤波技术

全面介绍了目前密集波分复用系统中的主流光滤波技术，包括介质薄膜滤波器、阵列波导光栅、光纤光栅、熔锥器件、奇偶交错滤波器和声光可调谐滤波器，从系统应用的角度分析了光滤波技术的发展趋势。     

基于光纤光栅级联调谐技术的波长检测系统

报道了一种检测光纤光栅传感器波长的新方案。实验系统采用新型的级联结构对电热调谐的光纤光栅滤波器进行复用,扫描分析传感信号光的峰值波长,同时用参考波长校准方法消除了电热调谐中的蠕动误差。结果表明,系统的检测范围可达23nm,波长分辨率为3.1pm,应变测量分辨率为2.56με。     

基于最小二乘法的电力电缆FBG传感测温系统

为了提高电力电缆测温系统的测量精度和速度,提出了以光纤梳状滤波器代替参考光栅提供拟合数据参考点,采用最小二乘法拟合光纤Bragg光栅波长和F-P可调谐滤波器调谐电压的线性关系,通过F-P可调谐滤波器解调FBG传感器中心波长变化的方法,完成对电力电缆温度的测量.研究表明,光纤梳状滤波器能够代替多个恒温参考光栅实现波长标定,对反射波长的测量误差＜5pm,温度均方误差≤0.7 ℃.     

光纤光栅复用调揩滤波检测系统的研究

提出了空分复用和同步滤波处理技术相结合的光纤光栅传感器波长检测方案。实验系统对光纤光栅滤波器进行空分复用 ,实现了对传感信号光的波长域分段同步滤波处理 ,检测范围为 2 1nm ,波长分辨率优于 7pm ,测试精确度可达± 0 .0 15nm ,达到了实用化要求。     

基于调谐滤波技术的光纤光栅传感解调系统

基于光纤光栅调谐技术,提出了动态滤波扫描、时域同步处理的新型波长检测方案。采用执行机构与监测单元相分离的光纤光栅调谐装置,运用同步滤波和处理的方法,并利用微机多通道采集技术实现了低成本、高精度的光纤光栅传感解调系统,测试表明该系统的波长分辨率为3pm,应变测量分辨率为2．55μ,扫描时间小于200ms,波长检测范围可达9．16nm。     

DWDM系统中的光滤波技术

密集波分复用光网络的不断演进带动节点器件技术飞速发展,光滤波技术作为其中的关键之一已不仅仅是原来狭义的复用/解复用器的概念,其涵盖的范畴越来越多,包括光分插复用(OADM)、光交叉连接(OXC)、增益平坦滤波(GFF)、色散补偿(DC)、泵浦合波器(PBC)、动态增益均衡器(DGE)、波长锁定器(Wave locker)等。滤波手段层出不穷,多腔介质膜滤波器(MDTFF)、阵列波导光栅(AWG)、光纤布拉格光栅(FBG)、熔融拉锥器件(FBT)、奇偶交错滤波器(Interleaver),此外还有声光可调谐滤波器(AOTF)、闪耀光栅、全息光栅、全光纤March-Zehnder干涉…     

可调谐光滤波器的研究

可调谐滤波器在光纤通信和光纤光栅传感中发挥了重要的作用.分别介绍了几种常用的可调谐光滤波的原理、结构和性能,分析了其发展趋势.     

超窄带宽可调光滤波器的研究

为了降低可调光滤波器的带宽,采用双光栅结构和基于微机电系统的反射镜相结合的方法,构建了具有波长连续可调谐的超窄带宽滤波器,并进行了理论分析和实验验证,取得了滤波带宽小于0.4nm的数据。结果表明,双光栅结构的光滤波器具有性能稳定、重复性优良的性能特点,并且很好地满足了带宽需求。这种结构显著降低了可调谐光滤波器的滤波带宽,提高了系统的稳定性。     

光纤光栅声光调制特性分析

高频超声波在紫外写入的光纤布拉格光栅(FBG)上传播，产生的长周期超声光栅调制光纤光栅，形成光纤超声超结构光栅。利用模式耦合理论，分析了光纤超声超结构光栅的光谱特性，得出光纤超声超结构光栅的反射谱存在多个反射峰，其反射峰的波长间隔由超声波的频率决定。因此，可以通过改变超声波的频率，调节一阶反射谱的反射波长，从而实现宽调谐范围的快速波长可调滤波器。该滤波器与通常的声光可调滤波器相比，带宽更窄，调谐速度更快。     

Analysis of a λ/4-phase-shifted doublephase-shift-controlled distributed feedback wavelength tunable opticalfilter

We have proposed a new λ/4-phase-shifted double phase-shift-controlled distributed feedback wavelength tunable optical filter structure. Theoretical analysis based on the transfer matrix method reveals that this filter can achieved a wavelength tuning range of 28.3 and 34.3 Å for the grating coupling coefficients of 6 and 10 mm, respectively. The filter has almost constant peak transmissivity (gain) of more than 30 dB within its tuning range, and its side-mode suppression ratio (SMSR) ranges from 15 to 34.7 dB     

Tunable wavelength filter using nano-sized droplets of liquidcrystal

An electrically tunable optical filter has been developed that uses a polymer containing fine droplets of nematic liquid crystal as the active cavity in a Fabry-Perot interferometer (FPI). This FPI filter, whose finesse was 62, had a free spectral range of 37 nm in the 1.55-μm range with a full-width at half maximum of 0.6 nm and a transmission loss of 2.4 dB. The polarization dependent loss was smaller than 0.17 dB. The transmitted peak wavelength decreased with an electric field. This resulted in a tuning range of 10 nm at 300 V. The switching time was about 370 μs     

1.5 μm two-section Fabry-Perot wavelength tunable optical filter

A 1.5 μm two-section Fabry-Perot wavelength tunable optical filter is studied. As opposed to DFB filters, this wavelength tunable optical filter has the advantage that the wavelength tuning range and the transmission bandwidth can be designed independently. This two-section Fabry-Perot filter also controls the transmissivity (gain) and the transmission wavelength independently by current injection and the constant-gain and constant-bandwidth wavelength tuning is achieved. The wavelength tuning range is as wide as 188 GHz (15 Å), the constant-gain is as high as 23 dB and the constant-bandwidth is as narrow as 5 GHz during wavelength tuning. A 25-channel wavelength selection with less than -10 dB crosstalk is expected with this filter     

1.5 μm phase-controlled distributed feedback wavelength tunableoptical filter

A 1.5-μm phase-controlled distributed feedback wavelength-tunable optical filter is studied. This is the first optical filter which controls the transmissivity (gain) and the transmission wavelength independently. Wavelength tuning range as wide as 43 GHz (3.4 Å) with high constant gain of 27 dB has been achieved. A five-channel wavelength selection with less than -10 dB crosstalk is expected with this filter. This device also operates as a wavelength tunable laser, and the wavelength tuning range as a laser is larger than as a filter. The reason is studied, and it is shown that suppression of the submodes is important to expand the wavelength tuning range     

机械可调的相移长周期光纤光栅

介绍了一种利用机械应力在普通单模光纤(SMF)中产生相移长周期光纤光栅(LPFGs)的简单方法。通过光弹效应，用有凹槽的平板制作LPFGs；用螺丝控制2个凹槽平板之间的距离，可以得到不同的相移值，实现了相移值的连续可调。光栅的传输光谱可以通过所加外力实现调谐，谐振峰强度的可调谐范围达到了16dB。该方法对于光栅光谱的调谐有很大的灵活性，可应用于掺Er光纤放大器(EDFA)的增益平坦。     

Flexibly tunable microwave photonic FIR filter incorporating wavelength spacing programmable, arrayed micro-mirror based optical filter

A novel tunable microwave photonic FIR filter incorporating a wavelength spacing tunable multiwavelength filter based on a programmable arrayed micro-mirror device (AMMD) is demonstrated. Owing to the unique characteristic of the AMMD, that an arbitrary optical filter shape can be produced by defining a desired spatial pattern on an array of /spl sim/800 000 micro-mirrors, a wavelength spacing tunable multiwavelength optical filtering pattern is readily obtainable. By controlling the optical filter wavelength spacing, flexible resonance RF frequency tuning is achieved over a range of 2.3 GHz.     

双信道解复用长周期光纤光栅的实验研究

长周期光纤光栅是近几年出现的一种波长选择滤波器件。利用其波长选择损耗特性,提出将之用于1310nm/1550nm波分复用系统的解复用。采用电弧熔融刻槽的方法,制备了长周期光纤光栅。并通过控制电弧放电过程和光栅的周期长短及周期数,得到了较为理想的谱特性。结果显示,其通道插入损耗能够小于0.5dB,20dB损耗阻带带宽可达15nm,信道隔离度估计约25dB。     

1.5 μm phase-shift-controlled distributed feedback wavelengthtunable optical filter

A 1.5-μm phase-shift-controlled distributed feedback wavelength tunable optical filter is studied. This wavelength tunable optical filter controls the transmissivity (gain) and the transmission wavelength independently by current injection. During wavelength tuning, the submode suppression ratio is large and a wavelength tuning range as wide as 120 GHz (9.5 Å) with 24.5-dB constant gain is achieved. An 18-channel wavelength selection with less than -10 dB crosstalk is expected with this filter. The effect of the light input, whose wavelength is in the sidelobe, on the transmission spectrum shape is shown     

全新布里渊散射可切换微波光子滤波器

提出了一个新的基于布里渊散射效应的微波光子滤波器。该滤波器可通过调谐系统中光滤波器的中心波长,实现高解析度带通滤波器与陷波滤波器之间的灵活切换,并且通过调谐产生受激布里渊散射的泵浦光的波长可实现滤波器通带或阻带的中心频率在很大频率范围内连续调谐。该滤波器为全光结构,因此具有非常大的调谐范围（调谐上限仅受限于试验中使用的矢量网络分析仪的显示频率上限）。系统中采用相位调制器,因此没有偏置电压漂移问题。实验结果展示了一个带通与陷波滤可灵活切换的高解析度微波光子滤波器,并且通带和阻带的中心频率在9～26.5 GHz范围内连续可调谐,其中带通滤波器的通带具有极窄3 dB带宽,约28 MHz（由光纤本身布里渊增益区线宽所决定）。     

机械可调谐的长周期光纤光栅的写制实验研究

深入研究了采用机械微弯法写制长周期光纤光栅(LPFG)的方案,进一步分析此方案中各种因素对LPFG特性的影响。写制的周期性凹槽板谐振波长变化率为17.7 nm/0.01 mm。当仅增加压力时,损耗峰值先增加,最大可调谐到16.248 dB。当压力过大时,损耗峰值减小。同时附加损耗随着压力增大而增加。而当压力一定时,损耗峰值随着周期性凹槽板的周期数目的增加而减小。研究结果有利于LPFG灵活运用于EDFA增益平坦和滤波应用等方面。