光纤光栅傅里叶变换光谱分析的研究

阐述了光纤光栅用作分光元件时 ,通过测量光纤光栅附近区干涉条纹 ,经快速傅里叶变换达到测量光谱的原理。讨论了波长测量范围和光谱分辨率。给出了在设计光纤光栅和确定探测器参数时应该考虑的几个问题。该光谱分析方法具有光谱分辨率高、结构简单、造价低等优点。     

增强现实显示衍射光波导的设计

提出了在波矢k空间中设计衍射光波导片的相关理论,系统仿真并研究了光线波长、光栅周期、光栅时钟角、波导基底折射率以及波导基底折射率色散对衍射光波导视场角以及相关设计参数的影响。设计结果表明,当使用宽光谱光源时,光谱带边缘波长的视场存在切割,对显示效果影响不大,衍射光波导片适用于宽光谱光源。波导基底折射率色散对衍射光波导设计的影响可以忽略。时钟角为40-270-140时,各个光栅区域位置及尺寸合适,适合于实际加工。本工作对衍射光波导的设计提供了积极的指导和借鉴。     

DWDM技术在新型波长解调方法中的应用

为实现光纤传感器的波长解调,以8通道50 GHz密集型波分复用器作为光纤光栅压力传感器中的解调工具,依据各个通道的中心波长作为波长的标定基准,利用从各通道中获得的光功率输出值获得光纤光栅反射光谱分布曲线的包络,并以高斯多项式拟合法作为光纤光栅波长寻峰算法,最终获得光纤光栅反射光谱的中心波长的准确位置,从而实现结构简洁、成本低廉、全光纤的波长解调系统,系统压力与波长的线性拟合度为0.996 5,实验测得的波长分辨率可达0.3 pm,最大引用误差为2.6%,测量精度为0.16 MPa。     

亚波长金属周期结构中表面等离子体相关机理和应用

研究了一种新型的有表面凹槽的亚波长金属光栅结构,通过改变表面凹槽填充物的折射率,可调控该结构的远场透射效率,在光学探测、生物传感等方面具有应用前景;结合金属波导理论,提出一种基于亚波长金属光栅波导结构的新型超分辨光刻方案,入射光波长为436 nm时,最高刻写分辨率可达34 nm.     

非对称结构阵列波导光栅解复用器的传输效率

基于光波导模场分布的高斯函数近似表达式,给出非对称结构阵列波导光栅解复用器信号通道对其中心波长光谱响应度的函数表达式,分析了光谱响应度与器件基本参数的关系.基于实际通道信号光谱分布的高斯函数近似表达,给出非对称结构阵列波导光栅解复用器信号通道对实际输入信号的传输效率,分析了输入信号光谱宽度对器件通道实际传输效率的影响.     

应力测量的光纤光栅调谐技术的研究

光纤光栅波长调谐在光纤传感领域中具有重要意义和实用价值。从理论上分析了基于悬臂梁的光纤光栅波长调谐的基本原理,阐述了等强度悬臂梁调谐技术及其特点。基于光谱分析仪0.1nm的光谱分辨率的测量,实验结果与理论分析一致。实验装置构形简单、成本低,有较好的线性,易于定标和操作。     

基于阵列波导光栅的单纤三重波分复用器

利用阵列波导光栅实现单纤三重波分复用器是一种具有很多优点的方法.ITU G.983标准规定了无源光网络的三个波长为1310,1490和1550nm,由于这三个波长的间距相差很大,光谱范围也大,用普通的AWG设计方法不能达到理想的效果.文中提出了一种基于阵列波导光栅的单纤三重波分复用器的新型设计,利用衍射光栅的频谱周期性,使离第二、三波长较远的第一波长工作在不同的衍射级次,并将第一波长映射到与第二、三波长形成几乎等间距信道的第四波长,从而减小了对光栅自由光谱范围的要求,同时使对应这三个工作信道的输入/输出波导几乎等间距,解决了传统设计方法导致的衍射级次小、器件尺寸大、制作困难等问题.     

基于阵列波导光栅的单纤三重波分复用器

利用阵列波导光栅实现单纤三重波分复用器是一种具有很多优点的方法.ITU G.983标准规定了无源光网络的三个波长为1310,1490和1550nm,由于这三个波长的间距相差很大,光谱范围也大,用普通的AWG设计方法不能达到理想的效果.文中提出了一种基于阵列波导光栅的单纤三重波分复用器的新型设计,利用衍射光栅的频谱周期性,使离第二、三波长较远的第一波长工作在不同的衍射级次,并将第一波长映射到与第二、三波长形成几乎等间距信道的第四波长,从而减小了对光栅自由光谱范围的要求,同时使对应这三个工作信道的输入/输出波导几乎等间距,解决了传统设计方法导致的衍射级次小、器件尺寸大、制作困难等问题.     

白光干涉法测量光纤布喇格光栅反射谱

为了实现光纤布喇格光栅反射谱的低成本测量,采用白光干涉技术搭建了一套结构简单的反射谱测量装置,利用该装置进行了实验,对所采集的干涉信号进行了数据处理,获得了光纤布喇格光栅的反射谱,光谱分辨率达到3pm,并对所测反射谱的光谱分辨率进行了理论分析.结果表明,利用该装置测得的反射谱具有良好的光谱分辨率,通过增加测量量程可以进一步提高光谱分辨率.     

一种降低列阵波导光栅相邻信道串扰的方法

阵列波导光栅 (AWG)作为波长滤波器在光通信领域具有很大的应用前景。串扰是影响阵列波导光栅应用的重要因素之一。为了降低阵列波导光栅相邻信道的串扰 ,本文提出并研究了一种降低阵列波导光栅的新方法。该方法利用阵列波导光栅的衍射特点性 ,通过调节阵列波导光栅的自由光谱范围 (FSR)、罗兰圆焦距和阵列波导数目 ,使得各信道信号的输出极小值处于其它信道输出波导中心 ,无次极大处于其它波导中 ,从而降低了阵列波导光栅的串扰 ,特别是相邻信道之间的串扰。通过光束传播方法 (BPM)的模拟了具有不同FSR的 1× 16阵列波导光栅 ,结果显示 ,该方法能将相邻信道之间的串扰降低约 5 .7dB。     

Fabrication and characterization of annealed proton exchanged long period waveguide grating in x-cut LiNbO3

In this paper, a long-period waveguide grating was fabricated in x-cut lithium niobate substrate by patterned annealed proton exchange waveguide fabrication process. The waveguide mode characteristic was evaluated using a charge-coupled device (CCD) camera. It shows that the waveguide is single mode transmission at a wavelength of 1 550 nm. The transmission spectra of the long period waveguide gratings were measured by optical spectrum analyzer (OSA) and show an extinction ratio of ~17 dB and a 3 dB bandwidth of ~10 nm at the resonant wavelength. The resonant wavelength moves toward to the long wavelength direction as the waveguide width-difference increases in the same period, and also shifts toward to the long wavelength direction with the increase of the period in the case of the same waveguide width-difference. The method of fabricating a long period waveguide grating based on a patterned annealed proton exchange technique simplifies the fabrication process, and at the same time, reduces the fabrication cost.     

啁啾光栅解调的准分布式光纤Bragg光栅传感器

为了提高光纤Bragg光栅(FBG)的应用范围.提出一种线性啁啾光栅(CFBG)解调的准分布式FBG传感系统.利用波导理论分析了CFBG特性;利用传输矩阵法推导了CFBG反射谱模型及波长与相位延迟的关系,并给出了相位延迟曲线.实验表明:所设计的系统应变测量范围为0～2000 με,温度测最范围为0～80℃;相位变化与被...     

Asymmetric twin-waveguide 1.55-μm wavelength laser with adistributed Bragg reflector

We demonstrate a single frequency, 1.55 μm wavelength laser based on an asymmetric twin-waveguide structure using a single growth step and a simple fabrication process. The external Bragg grating is formed on the passive ridge waveguide, optically coupled to the twin-guide gain section using a low loss, tapered mode transformer. The grating is produced by near-field holographic printing using a phase mask. Output powers >11 mW in a small-spot waveguide with a side-mode suppression ratio >40 dB and a slope efficiency of 0.11 W/A are obtained under pulsed operation. These performance characteristics are comparable to conventional, nonintegrated, conventional discrete DBR lasers, although the twin-waveguide design is compatible with photonic integrated circuits such as monolithic transmitters and WDM coherent receivers     

密集型多重体全息光栅波长解复用技术

阐述了光折变多重体全息光栅作为滤波器实现波长解复用的原理,分析了滤波器的波 长和角度选择特性,对器件设计中要考虑的问题进行了讨论。提出了实现多重体全息光栅波长解复用的实验方案和实用化要解决的问题。     

密集型多重体全息光栅波长解复用技术

阐述了光折变多重体全息光栅作为滤波器实现波长解复用的原理，分析了滤波器的波长和角度选择特性，对器件设计中要考虑的问题进行了讨论。提出了实现多重体全息光栅波长解复用的实验方案和实用化要解决的问题。     

Optimization of Thermo‐Optic Parameters for Temperature‐Insensitive LPWG Refractometers

In this paper, we report numerically calculated results of testing a temperature‐insensitive refractive sensor based on a planar‐type long‐period waveguide grating (LPWG). The LPWG consists of properly chosen polymer materials with an optimized thermo‐optic coefficient for the core layer in a four‐layer waveguide structure. The resonant wavelength shift below the spectral resolution of the conventional optical spectrum analyzer is obtained accurately over a temperature change of ±7.5°C even without any temperature control. The refractive index sensitivity of the proposed grating scheme is about 0.004 per resonant wavelength shift of 0.1 nm for an optimized thermo‐optic coefficient.     

基于表面等离子波耦合的流体波导光栅耦合器

提出了一种由金属光栅和流体光波导结构组成的,基于表面等离子波耦合的光栅耦合器。利用光栅的衍射效应,将金属光栅与介质分界面之间产生的表面等离子波耦合到流体光波导中,并且能够沿着流体光波导稳定地向前传播。通过采用基于有限时域差分算法的FDTD Solutions软件对光栅耦合器进行了参数优化及特性分析,通过优化使该结构在650 nm波长下的耦合效率达到56%。此外,由于该结构对TE偏振光和TM偏振光的选择比达到70∶1,因此具有偏振器的功能。同时由于TE偏振光耦合频谱的频带宽度仅为20 nm,该结构还具有窄带滤波的作用。此外,还研究了光栅结构参数、入射角以及流体折射率对耦合频谱的影响。     

Holographic grating fabrication for wide angular bandwidth using polymer thin films

To increase the angular bandwidth of volume holographic grating, we fabricate holographic gratings based on grating multiplexing technique by using thin films of photopolymers and polymer dispersed liquid crystals. Experimental results confirm that the liquid crystal materials increase the refractive index modulation of the grating, enabling high diffraction efficiency with wide angular response compared to pure polymer materials. We observe that the fabricated holographic grating has near 80% of diffraction efficiency and about 18° of angular bandwidth, which can be further improved by modifying the liquid crystal/polymer mixtures and the grating multiplexing technique. The grating can be used to fabricate holographic waveguide structures for emerging applications in the near-eye display systems.     

基于周期压力单模光纤长周期光栅的折射率传感特性研究

利用交替放置的两个相同周期性刻槽板,对放置于套管中的单模裸纤和待测媒质施力,形成了具有复合光波导结构的长周期光纤光栅(LPFG)。实验研究了不同折射率待测媒质对LPFG传输谱的影响。结果表明:复合波导光栅的光谱呈现双谐振峰现象,且中心谐振波长随待测媒质折射率增大向短波长方向移动;包层模阶次越高,其中心谐振波长移动量越大。当折射率从1.33变化到1.43时,LP14包层模的中心谐振波长变化了7.2nm,所对应的传感器折射率灵敏度约为2.78×10-4 RIU。     

Narrowing of the emission spectra of high-power laser diodes with a volume Bragg grating recorded in photo-thermo-refractive glass

The spectral characteristics of a high-power semiconductor laser with an external cavity in which longitudinal-mode selection is implemented by means of a holographic volume Bragg grating recorded in photo-thermo-refractive glass are investigated. Mode selection leads to narrowing of the spectrum of the laser diode from an initial width of 6 nm to 5 Å. In the narrowed spectrum, a fine structure representing a set of eigenmodes that correspond to the length of a laser chip is resolved. The number of these modes is limited by the width of the spectral selectivity curve of the grating. It is shown that insertion of the grating into the cavity leads to severalfold enhancement of the grating selectivity. It is demonstrated that the implemented external-cavity design makes it possible to smoothly tune the laser emission wavelength in a 10-nm range.