用于波分复用系统的多峰干涉滤光片

介绍了用于波分复用系统的多峰干涉滤光片的设计原理,提出了滤光片透射峰位置的确定方法,讨论了影响滤光片半宽度和截止度的因素,给出了滤光片的膜厚容差分析结果,表明透射率监控标准偏差在<0.5%范围内,可以得到波形良好的多峰滤光片,最后给出了实验结果.     

具有鲁棒性的矩形窄带滤光片的自动设计

分析了用于WDM光纤通信系统的全介质多腔窄带滤光片的膜系结构特点及其所必须具备的光学特性,提出了一种利用最优化方法的原理,通过计算机寻优来自动完成其膜系设计的方法;构造了合理的评价函数,编制了可自动搜索既满足设计目标、又具有鲁棒性的最优化膜系的计算机程序;使用本程序所设计出的多腔窄带滤光片具有较小的纹波系数和较好的矩形度,可满足WDM光纤通信系统对其分波/复波器的要求.     

基于遗传算法的斜入射窄带滤光片膜系优化设计

根据薄膜窄带滤光片在斜入射时的偏振特性,提出了基于遗传算法的斜入射薄膜窄带滤光片膜系优化设计方法.根据开发的程序,设计并制备了一组可用于18°倾斜入射的0.8纳米信道间隔的五腔薄膜窄带滤光片.该滤光片能有效地抑制斜入射时偏振光中心波长的分离现象,降低器件的偏振相关损耗,通过角度调谐能实现选择波长的改变.通过与针法设计的滤光片膜系相比,遗传算法得到的膜系具有更高的矩形度、更大的波长调谐范围以及更低的偏振相关损耗.实验结果表明其满足设计要求并有超过25纳米的波长调谐范围.     

DWDM极窄带干涉滤光片的误差与自动补偿效应

针对现代光通信中的核心元件之一--密集型波分复用(DWDM)系统中极窄带光学薄膜干涉滤光片的指标要求,提出采用基于四分之一波长的规整膜系是实现密集型波分复用功能的最佳选择.对给定的设计方案的各个膜层的误差灵敏度分布、特定膜层的误差成因进行了分析,并对多个膜层进行了随机分布的误差模拟.通过对直接极值法监控中不同误差的补偿机理的研究,指出采用直接极值法监控是目前为止镀制这种滤光片的有效方法.最后讨论了可能存在的两种系统误差.     

角度调谐滤光片特性分析及膜系设计

对窄带滤光片的倾斜入射特性作了分析.斜入射时其透射通带和峰值会向短波方向移动,透射曲线的稳定性跟滤光片的间隔层结构相关,多腔间使用相同的间隔层可以保证斜入射时有稳定的峰值透射率和带宽,利用该特点可以制备角度调谐窄带滤光片.透射光S和P偏振分量的中心波长随入射角度的增大出现分离现象,产生较大的偏振相关损耗.通过搭配不同厚度的高低折射率材料作为间隔层,改变其有效折射率,使其两个偏振分量的中心波长实现重合.设计了符合密集波分复用(Dense Wavelength Division Multiplexing,DWDM)系统要求的低偏振相关损耗四腔窄带角度调谐滤光片膜系,其可调谐范围达20 nm以上,并评估了所设计角度调谐滤光片的调谐性能.     

镀窄带干涉滤光片用的直控极值法

直控极值法具有自动补偿各层膜的光学厚度的优点,至今仍被人们广泛采用.但在镀制窄带滤光片的最末几层时,有时会因出现反常现象而带来巨大误差,甚至失灵.本文用电脑模拟了滤光片的镀制过程,分析了出现反常现象的原因,从而提出了改进及消除这种现象的措施.结果表明:可以用带宽小于所镀滤光片的通带半宽度的光束来进行膜厚监控.     

光锥角对窄带滤光片透射率的影响及补偿方法

全介质膜窄带滤光片因具有优良的光学性能、较强的工艺性和空间环境适应性被广泛应用于空间多光谱遥感仪器中,但锥光束入射导致的中心波长漂移问题严重影响此类窄带滤光片的光谱选择性能。为了研究光锥角对窄带滤光片透射率特性的影响,设计了非规整型全介质膜窄带滤光片,分析了高斯光束倾斜入射窄带滤光片导致透射率的变化,建立了非均匀照度下锥光束正入射时窄带滤光片等效透射率的求解模型,定量求解了等效透射率及中心波长漂移量,并对理论模型进行了实验验证。结果表明,锥光束正入射对窄带滤光片透射率的影响主要表现为中心波长的蓝移;在镀膜工艺相对稳定的基础上,理论模型的等效透射率预测精度优于中心波长的0.15%。所以,可以使用等效透射率求解模型定量计算锥光束正入射导致窄带滤光片透射率的变化,并利用中心波长漂移量修正后的设计数据指导滤光片镀膜,进而实现窄带滤光片的高精度光谱选择,这为解决介质膜窄带滤光片因锥光束入射导致的中心波长漂移问题提供了新的技术途径。     

等离子体辅助制备窄带滤光片

研究了采用等离子辅助技术制备窄带滤光片的工艺。介绍了等离子辅助蒸镀系统的基本工作原理,描述了优化膜厚均匀性的过程。在有色玻璃上制备了由多层TiO2和SiO2薄膜组成的窄带滤光片,测试并分析了窄带滤光片的性能。试验结果表明,采用等离子体辅助蒸镀技术能够批量制备具有优良光学性能的窄带滤光片。     

带缓冲层的导模共振滤光片反射光谱特性

将均质多层膜系设计中的缓冲层概念引入到反射导模共振滤光片的设计中,以研究缓冲层的增加对导模共振滤光片反射光谱特性的影响.设计并通过严格的耦合波理论计算了一、二、三、四通道导模共振反射滤光片光谱特性.在膜系设计中增加缓冲层后.随着其厚度的逐渐增加.反射光谱中依次出现二、三、四个窄带反射峰;缓冲层厚度为796.35 nm时.当滤光片光栅层占空比在0.2～O.9范围内、光栅深度在100～200 nm变化时,共振峰的位置、反射率峰值高度几乎不变,保持了很好的多通道滤光片特性.     

角度调谐滤光片带宽消偏振研究

倾斜入射时薄膜窄带滤光片的s和p偏振光的带宽会随着入射角度的增大出现分离,限制了滤光片的调谐范围。分析了偏振光带宽分离现象出现的原因和其与滤光片镜层膜系结构的关系,并得到了消除偏振光带宽分离现象的方法。根据该方法对前期设计的100GHz密集波分复用(DWDM)系统四腔角度调谐窄带滤光片进行了改进,结果表明,该方法能有效的解决偏振光带宽的分离问题,扩大调谐范围。     

Integrated optical filter arrays fabricated by using the combinatorial etching technique

A combinatorial etching technique is developed to fabricate integrated narrow bandpass filters on a single substrate. It is highly efficient for fabrication of integrated filter arrays in optical regions. A monolithic filter array has been fabricated by using the technique with a two-step deposition process. The filter contains 32 elements in the near-infrared region. The relative full width at half-maximum (FWHM) sigmalambda/lambda of the filter elements is less than 0.2%. Such a narrow bandpass filter array can be utilized in many optical applications.     

大角度蚀刻衍射光栅的模拟

研究了平面波导密集波分复用器件中很有发展潜力的蚀刻衍射光栅(EDG).小角度范围光栅的模拟通常采用高斯近似的输入光场,由于近轴的高斯光场接近实际光场,所以模拟结果很准确.但这种方法应用于大角度范围的光栅则有偏差.本文提出了大角度蚀刻衍射光栅的模拟方法,分析了这种偏差并给出了模拟结果.事实上这种方法也适合于实际任意输入光场的模拟.     

密集型波分复用薄膜干涉滤光片的设计

介绍了波分复用系统对薄膜干涉滤光片的基本要求，为了满足这些要求，一方面需要精心选择基板和薄膜材料，另一方面要寻找性能优良，制造容易的膜系，文中提出了二种适宜于设计这种滤光片的方法。     

Multiple narrow bandpass optical filters based on one-dimensional rugate photonic structures of two periodicities

A theoretical analysis of a design of multiple narrow bandpass filters based on one-dimensional (1D) rugate photonic structures with a period jump defect is presented. The optical properties, including transmittance and energy density distributions, are numerically calculated using the propagation matrix method. Our results show that multiple resonance transmission modes are produced when the period jump defect is introduced into the 1D rugate film. Both blueshift and redshift of the stop band of the rugate structure and wavelengths of resonant modes are observed, depending on the change of period jump. The number, the wavelengths, the band intervals, and the intensities of multiple resonance transmission modes are tunable by adjusting structure parameters of the rugate structure. Experimental feasibility of the proposed multiple narrow bandpass optical filters using the technique of glancing angle deposition is also discussed.     

一种双反射壁型二维光子晶体窄带滤波器

提出了一种基于双反射壁型结构的光子晶体窄带滤波器, 该滤波器由一个单模谐振腔和两个反射壁构成. 通过调节谐振腔与反射壁之间的距离可以改变滤波谱线的带宽. 利用时域有限差分法进行仿真分析, 结果表明, 该滤波器的工作频率在193.40 THz附近, 带宽小于5.9 GHz, 峰值透射率高达94%, 工作区域长度仅有9 μm. 该器件可应用于密集波分复用系统.     

128 channels of integrated filter array rapidly fabricated by using the combinatorial deposition technique

A combinatorial deposition technique is developed to fabricate integrated narrow bandpass filters (NBPFs) on a single substrate. It is highly efficient for the fabrication of integrated filter arrays in optical regions. An array integrated with 128 NBPFs has been fabricated by using the technique in a nine-step deposition process. The pass bands of the filters distribute almost linearly in the range of 722.0∼880.0 nm. The relative bandwidth of the pass bands is smaller than 0.44%. Such a NBPF array can be utilized as a wavelength division component in many optical applications. It is very powerful for the miniaturization of relevant apparatuses. PACS 42.79.Ci; 84.30.Vn; 42.82.Cr; 42.82.Gw     

Fabrication of broadband antireflection coatings using broadband optical monitoring mixed with time monitoring

Multi-layer optical coatings with complex spectrum requirements, such as multi-band pass filters, notch filters, and ultra-broadband antireflection coating, which usually contain very thin layers and sensitive layers, are difficult to be fabricated using a quartz crystal monitoring method or a single wavelength optical monitoring system(SWLOMS). In this paper, a broadband antireflection(AR) coating applied in the wavelength range from 800 nm to 1800 nm was designed and deposited by ion beam sputtering(IBS). Ta_2O_5 and Si O_2 were chosen as high and low refractive index coating materials,respectively. The optimized coating structure contains 9 non-quarter-wave(QW) layers totally with ultra-thin layers and sensitive layers in this coating stack. In order to obtain high transmittance, it is very important to realize the thickness accurate control on these thin layers and sensitive layers. A broadband optical monitoring mixed with time monitoring strategy was successfully used to control the layer thickness during the deposition process. At last, the measured transmittance of AR coating is quite close to the theoretical value. A 0.6% variation in short wavelength edge across the central 180 mm diameter is demonstrated. A spectrum shift of less than 0.5% for 2 continuous runs is also presented.     

Synthesis of bandpass grid filter for linear polarized millimeter wave

A method based on equivalent circuit and transmission line model is proposed to design narrow bandpass grid filters in short millimeter wave. Several bandpass filters with 2, 3 or 4 element inductive wire grids in the 70GHz region have been designed with Butterworth or Chebyshev characteristic for linear polarized wave. The agreement between measurement and design theory is good and this proves the rationality and practicality of our design theory.     

极值法膜厚控制的误差分析及其改进设计

分析了光学薄膜厚度的极值控制法,并利用矩阵的方法给出了极值法膜厚控制误差。基于极值法膜厚控制的原理,利用由IC/5薄膜沉积控制器和晶震探头组成的反馈系统,控制蒸发速率的大小,光控的信号由可编程的计算机探测接收。分别对ZrO2/SiO2,膜料进行了两组交替镀制实验测试。结果表明,整个系统稳定性好,自动化程度高,膜厚控制精度在1 02%左右。