紫外写入光纤光栅用亚μm相位掩模板制作误差容限分析

本文采用电磁波标量衍射理论研究了紫外写入光纤光栅用亚μｍ相位掩模的近场衍射特性，并据此得出了零级衍射抑制的条件，２数值模拟方法研究了相位掩模制作误差对有衍射抑制的影响，分析表明，为使零级衍射效率小于５％，相位掩模的刻槽深度和占空比制作误差必须控制在／△ｈ／〈３８ｎｍ和／△ｆ／〈０．１１的范围内。     

光纤光栅制作及其温度稳定性研究

用波长为２４８ｎｍ的ＫｒＦ准分子激光和零级抑制的石英相位模版在Ｂ－Ｇｅ共掺单模石英光纤上研制成功反射率达１００％的均匀光纤布拉格光栅（ＦＢＧ），并对ＦＢＧ的温度稳定性进行了研究。本文给出ＦＢＧ制作实验装置、实验结果以及关于ＦＢＧ温度稳定性的实验研究结果。     

线性啁啾相位掩模的研制

利用严格耦合波理论分析了线性啁啾相位掩模的衍射特性,得到只有当相位掩模的占宽比在0.37～0.50之间,槽形深度在242～270 nm之间时,才能保证零级衍射效率小于2%.同时正负一级的衍射效率大于35%.在此基础上,利用全息一离子束刻蚀和反应离子柬刻蚀相结合的新方法,制作了中心周期为1000 nm,啁啾率1 nm/mm,有效面积为100 mmX10 mm的线性啁啾相位掩模.发现先用短时间Ar离子束刻蚀对光刻胶光栅掩模槽形进行修正,然后采用CHF3反应离子束刻蚀,能得到更合适的占宽比,从而确定了刻蚀新工艺.实验测量表明其零级衍射效率小于2%,正负一级衍射效率大于35%,最大非线性系数为1.6%.理论分析表明该相位掩模能够满足制作线性啁啾光纤光栅的需要.     

制作光纤光栅用相位掩模的衍射行为研究

利用严格耦合波理论对用于光纤光栅制作的相位掩模的衍射特性进行了深入的研究.研究发现,在紫外写入波长(248 nm)下,为了使零级衍射效率＜5%,且±1级的衍射效率＞35%,相位掩模的刻槽深度必须控制在230～280 nm,占宽比必须控制在0.48～0.65.同时,与标量衍射理论的结果进行了分析对比.这些都为相位掩模的实际制作提供了有意义的结果.     

用相位掩模光刻制作光纤内的布拉格光栅

用相位掩模光刻制作光纤内的布拉格光栅用相位掩模光刻法已把布拉格光栅写入光纤和平面玻璃结构。由加拿大通讯研究中心发展的这种技术通过简化的非全息工艺而用来制作光敏波导内的优质布拉格光栅。相位掩模的作用是使紫外光源相位空间调制，而使光敏玻璃纤维的局部折射率...     

相位掩模法制造光纤光栅的理论分析

推导出了用相位掩模法制造光纤光栅的理论根据，得出相位掩模法中常见的一些有用公式，并报道了实验结果。     

啁啾光纤光栅相位掩模槽形控制新方法研究

在啁啾光纤光栅相位掩模的制作中,针对光刻胶光栅槽形要求比较高的问题,提出离子束刻蚀和反应离子束刻蚀相结合的方法,来实现对相位掩模槽形占宽比的控制.运用高级线段运动算法模拟分析刻蚀中的图形演化,用Ar离子束刻蚀对光刻胶光栅掩模形貌进行修正,然后采用CHF3反应离子束刻蚀,实验和模拟均表明,Ar离子束刻蚀能很好的改善掩模与基片交界处的基片侧壁形貌,使得在CHF3反应离子束刻蚀下能得到较小的占宽比.对槽形控制提供了有意义的实验手段.     

对称傅里叶系统中二元光学元件的算法研究与设计

讨论了二元光学元件的计算机设计方法，并给出了傅氏系统中设计二元光学元件的运算程序，给出了光学互连系统中所用的二元光学元件的掩模图形．我们知道，在对称傅里叶系统中，由于输出平面上的光强分布是平面对称的，由傅里叶交换的性质，应该有，而由虽然在n较大时，Ck与Ck＋1的差别不是太大，但是毕竟也是带来误差的原因之一，况且在二元光学元件的掩模图形计算中还采用了多次叠代和等级量化等近似方法，可能累积增大误差，因此不能忽视．我们根据设计衍射相位元件的计算流程图编制程序，计算了几种衍射相位元件的相位分布，绘制了掩模…     

周期性相位掩模用于图象加密的研究

提出了一种新的行之有效的图象加密方法．即利用两个彼此独立的周期性相位掩模分别对需要保护的图象在空域和Fourier频域进行编码，使原始图象变成噪声。其特点是解密时对相位掩模的对准精度有一定的宽容度．而且由于该相位分布具有周期性，是密钥的合法持有者唯一掌握的确定性函数，所以可以重构，给实际应用带来了便利。     

GaAs器件工艺中等离子刻蚀及计算机辅助监控技术研究

用Ｎ２气和ＮＦ３反应气体，在较低的刻蚀功率下实现了用薄正性光刻胶ＡＺ１５１８作掩模，均匀、快速刻蚀ＳｉＯ２，ＳｉＯＮ，Ｓｉ３Ｎ４，ＷＮ，Ｗ等材料的等离子刻蚀技术。利用到蚀过程中射频参数的变化和计算机技术，将射频参数的变化在计算机屏幕上实时显示，实现了计算机辅助监控和终点检测技术。     

Fabrication and characterization of high-quality uniform and apodized Si/sub 3/N/sub 4/ waveguide gratings using laser interference lithography

A method is presented for fabricating high-quality ridge waveguide gratings by combining conventional mask lithography with laser interference lithography. The method, which allows for apodization functions modulating both amplitude and phase of the grating is demonstrated by fabricating a grating that is chirped by width-variation of the grated ridge waveguide. The structure was optically characterized using both an end-fire and an infrared camera setup to measure the transmission and to map and quantify the power scattered out of the grating, respectively. For a uniform grating, we found a Q value of /spl sim/8000 for the resonance peak near the lower wavelength band edge, which was almost completely suppressed after apodization.     

Minimization of phase errors in long fiber Bragg grating phase masks made using electron beam lithography

Centimeter-long fiber Bragg grating phase masks having several thousand periods are fabricated using electron beam lithography and require the stitching together of many electron beam writing fields. Two techniques are used to minimize the effect of phase errors arising from the stitching process. Fiber Bragg gratings with more than 99.9% reflectivity are photoimprinted using the phase masks and near perfect spectral response is obtained in spite of stitching errors.     

A novel dual-wavelength fiber Bragg grating and its application in fiber ring laser

A novel method for fabricating dual-wavelength fiber Bragg gratings (FBGs) by using one phase mask is developed. The method is based on a double-exposure technique. Our technique lends itself to writing gratings with controllable reflectivity and separation of two Bragg wavelengths. A grating with two equal transmission peaks of 20.25 dB is obtained by this method and the separation of the two Bragg wavelengths is about 0.8 nm. With the grating, we demonstrate a dual-wavelength erbium-doped fiber ring laser whose interval of the two peaks is 0.8 nm. The laser's peak powers can get 3.1 mW above and have a good stability.     

Group delay ripple reduction and reflectivity increase in a chirpedfiber Bragg grating by multiple-overwriting of a phase mask with anelectron-beam

The phase errors in electron-beam-written step-chirped masks can be reduced by using a method based on the continuous movement approach and overwriting a pattern at the same place on the substrate several times. The group delay ripple of chirped fiber Bragg gratings fabricated by a four-times-overwritten phase mask is comparable with that of gratings obtained using a holographically written chirped phase mask     

二元相位光栅抗反射特性的耦合波分析

运用Ｍａｘｗｅｌｌ方程组和电磁场的边界连续条件，本文导出了二元相位光栅的严格的耦合波方程，分析了二元相位光栅的抗反射特性。在适当选取光栅的几何参数时，光栅的反射率可以减至几乎为零。实验测试结果与理论值基本相符。     

深刻蚀高密度熔融石英光栅

深刻蚀高密度熔融石英光栅是一种新型高效的衍射光学元件,具有衍射效率高、成本低、抗损伤,能在高强度激光条件下工作等优点。给出了利用感应耦合等离子体(ICP)技术制作熔融石英深刻蚀光栅的详细过程,并在一定的优化条件下制作了一系列不同周期、开口比和深度的高质量深刻蚀石英光栅。实验得到的最大刻蚀深度为4μm,并且在600 l/mm的高密度条件下得到了刻蚀深度为1.9μm的高深宽比石英光栅。光栅侧壁陡直,表面平整,没有聚合物沉积。所制作的熔融石英光栅元件在高强激光环境、光谱仪、高效滤波器和波分复用系统等领域中有非常广泛的用途。     

全息拼接光栅的误差研究

为了制作大面积拼接光栅,对全息光栅拼接误差进行了分析。利用参考光栅与光场光栅形成的莫尔条纹来控制拼接光栅位置和误差,确定了参考光栅莫尔条纹间距、倾斜度及相位与拼接光栅位置之间的关系。研究了参考光栅面和拼接光栅基片不平行时莫尔条纹与拼接光栅条纹的相位一致性,计算了光程差漂移对拼接光栅相位对准误差的影响,分析了工作平台移动对光栅拼接误差的影响。得出光栅拼接总误差为0.15λ,该误差接近光栅拼接精度要求,通过实验验证了全息光栅拼接误差分析的正确性。结果表明,利用参考光栅进行全息光栅拼接是可行的。全息拼接光栅的误差分析为制作米量级高精度拼接光栅提供了理论支持。     

Cascade self-induced holography: a new grating fabricationtechnology for DFB/DBR lasers and WDM laser arrays

A method of fabricating submicron gratings for optoelectronic devices from a glass mask was proposed and demonstrated. The glass mask has gratings on both sides with a period of at least four times the final feature size. By introducing an offset to the grating periods on the mask, one can achieve multiple-period gratings with a very fine period spacing for advanced wavelength-division multiplexing (WDM) devices. In this paper, we demonstrated 0.5-μm second-order gratings for 1.55-μm DFB lasers and gratings with a 6-Å period difference for a four-channel WDM laser array using only optical sources. The Moire pattern caused by the spatial frequency beating was also observed and discussed. The Moire pattern could serve as an effective tool to measuring wavelength channel spacing between devices with an unprecedented (0.1 Å) resolution     

Group-delay ripple reduction in step-chirped fiber Bragg gratingsby using laser-beam written step-chirped phase masks

Step-chirped phase masks for step-chirped fiber Bragg gratings (FBGs) were fabricated by employing a new writing strategy, in which the beam is able to scan a step-chirped pattern all at once or continuously. This new writing strategy was realized by using a raster scan-type laser-beam writing system. Linearly and nonlinearly step-chirped FBGs, fabricated by using these masks, show very low group-delay ripple characteristics, which means that the masks have fewer stitching errors than conventional step-chirped masks