基于圆柱型硅光子晶体的1×2光下路分束器(英文)

本文设计了一个基于圆柱型硅光子晶体自准直环形腔的1×2光下路分束器.该光下路分束器由三个分光镜和一个反射镜构成,其中窄光束依赖自准直效应进行传输.利用多光束干涉理论分析了光下路分束器中不同出口的理论透射谱,并且利用时域有限差分法对光下路分束器透射谱进行数值模拟计算,其结果与理论预测基本一致.当下路波长为1 550nm时,光下路分束器的自由光谱范围约为30nm,几乎涵盖了整个光通信C波段.由于其小尺寸和全硅材料,本文设计的1×2光下路分束器有望应用于未来的集成光路中.     

基于圆柱型硅光子晶体的1×2光下路分束器

本文设计了一个基于圆柱型硅光子晶体自准直环形腔的1×2光下路分束器.该光下路分束器由三个分光镜和一个反射镜构成,其中窄光束依赖自准直效应进行传输.利用多光束干涉理论分析了光下路分束器中不同出口的理论透射谱,并且利用时域有限差分法对光下路分束器透射谱进行数值模拟计算,其结果与理论预测基本一致.当下路波长为1 550 nm时,光下路分束器的自由光谱范围约为30 nm,几乎涵盖了整个光通信C波段.由于其小尺寸和全硅材料,本文设计的1×2光下路分束器有望应用于未来的集成光路中.     

分束量可调的等光程平行分束技术

基于厚波片平行分束特性,提出了一种分束量可调的等光程平行分束技术,给出透射式和反射式两种平行分束光路.透射式平行分束光路由厚波片和1/2波片组成,反射式平行分束光路由分束镜、厚波片、1/4波片和反射镜组成.通过旋转厚波片可实现分束量的调节.实验结果和理论值相吻合,验证了该技术的有效性.     

分束量可调的等光程平行分束技术

基于厚波片平行分束特性,提出了一种分束量可调的等光程平行分束技术,给出透射式和反射式两种平行分束光路.透射式平行分束光路由厚波片和1/2波片组成,反射式平行分束光路由分束镜、厚波片、1/4波片和反射镜组成.通过旋转厚波片可实现分束量的调节.实验结果和理论值相吻合,验证了该技术的有效性.     

基于非球面透镜的光分束器设计

 针对目前532 nm波长光的分束技术在光电测控系统（如激光干涉测速）等领域的广泛应用,提出一种光分束器的设计方法,此分束器可将光纤入射的532 nm绿光分成接近等比的多束光（包括一分二、一分三、一分四）。此系统首先用非球面透镜将光纤入射的光束准直,再通过分光片分光后用同样的透镜将光束耦合进光纤,达到了77%的通光效率,附加损耗约1 dB。详细介绍了非球面透镜的设计、分束器的结构、装配及其实验结果,并对实验结果以及研制过程中影响分束器效率的各种因素进行分析。     

二维可调平行分束器

这是一种把单一激光束变成两束偏振方向相互垂直、距离和强度连续可调的平行光束的方法和装置.结构如图1所示.该装置由一个偏光镜、一个偏光分束镜、一个45°玻璃棱镜和一对可调两平行光束距离的光楔组成.旋转偏光镜,即改变了入射到偏光分束镜上光的偏振面,据马吕斯定律可知,它使得经偏光分束镜出来的两束光强度比可为任意值.当偏光镜转到某一特殊位置时,只有一束光出射,移动一光楔,即改变了两光楔的相对位置,可改变两平行出射光束的距离.两光楔同时绕以入射光为轴旋转,可改变两平行光束的相对方位;两种调节相结合,可使其中一光束位置不动,…     

空间调制傅里叶变换红外光谱仪干涉系统透射效率研究

光学系统表面的反射与材料的吸收会降低空间调制傅里叶变换红外光谱仪中光的透过率。通过对干涉系统透过率函数的计算和对采样干涉图与复原光谱的仿真,结果显示透过率函数作用下的干涉图像对比度下降,复原光谱中的谱线强度发生衰减。分析表明,干涉图像对比度的下降主要是由分束器对入射光的有效反射引起的,而谱线强度的衰减则是由与增透膜的光强反射率R₁、分束膜的光强反射率R₂和材料的吸收系数α有关的透射效率函数所决定。通过分析论证,对于本文所研究的光谱波段,可以不考虑材料的吸收,所以透射效率主要由R₁和R₂决定。由此,将透射效率作为设计指标,根据系统的设计需求,就可以得到增透膜与分束膜光强反射率的容限值。     

基于时域有限差分算法的光子晶体光分束器的设计

报道了一种基于空气孔型光子晶体自准直环形谐振腔1×4光分束器。其结构由4个改变空气孔半径的分光镜组成。首先运用多光束干涉原理分析光分束器各个端口的透射谱,通过分光镜的合适组合,自准直光就可以按照设定的比例从各出口出射。再利用编写的二维时域有限差分程序进行数值模拟计算,其结果和理论值很好地吻合。该结构具有尺寸小、自由光谱范围大、硅基等优点,有望应用于未来的高密度集成光路中。     

13.9nm软X射线激光用大面积多层膜分束镜研制

 基于分束镜反射率和透射率的乘积为衡量标准的原则,设计了13.9nm软X射线激光干涉测量所需的多层膜分束镜，用磁控溅射法在有效面积达10mm×10mm，厚100nm的氮化硅窗口上镀制Mo/Si多层膜,实现了分束镜制作。用表面轮廓仪实测分束镜面形精度达到nm量级，同步辐射反射率计测试表明,分束镜的反射率和透射率乘积约4%。     

TM模式介质柱光子晶体1×5光分束器

提出了一种利用自准直效应基于TM模式二维光子晶体的1×5光分束器。该结构由两个环形谐振腔级联而成,每个环形谐振腔有4个可改变介质柱半径的分光镜。首先运用多光束干涉原理分析光分束器中各个端口的透射谱,按照设置的比例对8个分光镜进行合适的组合,自准直光束即可从5个出口出射,达到1×5分束器的效果;然后利用时域有限差分软件方法来对数值进行模拟,其结果和理论值吻合地较好。该结构尺寸较小,自由光谱范围大,在未来的高密度集成光路中会有较好的应用前景。     

Photonic drop splitters based on self-collimation ring resonators in a silicon photonic crystal

We report here 1 × 3 and 1 × 2 photonic drop splitters (PDSs) with different splitting ratios based on self-collimation ring resonators (SCRRs) in an air-hole silicon photonic crystal. An 1 × 3 PDS consists of four beam splitters and an 1 × 2 PDS consists of three beam splitters and one mirror. Light propagates in the PDSs employing self-collimation effect. The theoretical transmission spectra at different drop ports in PDSs were analyzed with the multiple-beam interference theory. Then they were investigated with the finite-difference time-domain (FDTD) simulation technique. The simulation results agree well with the theoretical prediction. For the drop wavelength 1550 nm, the free spectral range of the PDSs is about 29 nm, which almost covers the whole optical communication C-band window. Because of small dimensions, air-hole structure and whole-silicon material, the proposed PDSs hold great potentials for applications in photonic integrated circuits.     

Archimedes 32,4,3,4结构光子晶体中与偏振无关的自准直分束器

通过等频图分析并结合时域有限差分法法模拟, 在Archimedes 3²,4,3,4结构排列的二维光子晶体中同一频率下同时实现了电磁波两种偏振态的自准直. 研究发现,在该结构光子晶体中引入缺陷,当线缺陷宽度改变时, TE和TM两种偏振态光束的分束效果将会随之变化.由此通过控制缺陷宽度,分别实现了两种偏振态光束的50% ∶50%分束以及90°大角度光折弯,分束和折弯的效率都较为理想,为未来设计基于光子晶体的新型光子学器件提供了一种新的思路.     

Ultra-broadband polarization splitter based on graphene layer-filled dual-core photonic crystal fiber

An ultra-broadband polarization splitter based on graphene layer-filled dual-core photonic crystal fiber(GDC-PCF)that can work in a wavelength range from 1120 nm to 1730 nm is proposed in this paper. Through optimizing fiber configuration, the polarization splitter has an extinction ratio of-56.3 dB at 1.55 μm with a fiber length of 4.8 mm.Compared with the photonic crystal fiber reported splitters, to our knowledge, the GDC-PCF splitter with the extinction ratio below-20 dB has a super wide bandwidth of 610 nm. Due to the excellent splitting characteristics, the GDC-PCF will be used in coherent optical communication systems in a wavelength range from infrared to mid-infraed.     

Polarization beam splitters based on a two-dimensional photonic crystal of negative refraction

A two-dimensional metallo-dielectric photonic crystal of negative refraction was designed for the application of polarization beam splitters. To match the refractive index of air, the effective refractive index of the designed photonic crystal is -1 for TE polarization and +1 for TM polarization. Two types of polarization beam splitter are presented.     

Relaxed fabrication tolerance for self-imaging photonic crystal waveguide splitters using a tapered multimode interference region

The power imbalance between different waveguide outputs is compensated by manipulating the dispersion of the guided propagation in the multimode interference (MMI) region. This is attainable using a tapered region at the beginning of the MMI region that has been verified through simulation and experiment. From this, the fabrication tolerance for the diameters of holes in a tapered 1×3 photonic crystal waveguide (PhCW) splitter is relaxed up to a range of at least 27 nm. The output power is well-balanced to within 1 dB. The effective bandwidth of the splitters shifts only around 13 nm, for a reduction of 10 nm in the diameter of the PhCW holes. The optimized component is an outstanding ultracompact 1×3 splitter for the photonic integrated circuit (PIC).     

光子晶体偏振分光镜的优化设计

提出了一种二维光子晶体偏振分光镜的设计方法,介绍了光栅基板上用Ge/BaF₂ 多层膜实现二维光子晶体偏振分光镜的优化设计.结果表明，TE模式的光子禁带宽度为0083(2πc/a, a是光栅的周期),设计的偏振波长从172μm到24μm，相对带宽为331％.此光子晶体偏振器件制作简单,具有实用性. 关键词： 偏振分光镜 光子晶体 光子禁带     

Dispersion-based beam splitter in photonic crystals

A novel implementation of a dispersion-based beam splitter in a photonic crystal (PhC) is proposed. The beam splitter consists of two periodic structures: a nonchannel dispersion-guiding region and a splitting structure operating inside the photonic bandgap. The dispersion-guiding PhC structure is used to route the optical wave by exploiting the dispersion properties of the lattice. An arbitrary power ratio between the output beams can be achieved by varying the parameters of the splitting structure. Within the studied range of splitting structures, high output power was observed and verified experimentally.