Study of Deep-etched Glass Waveguide Grating

Photoresist grating was fabricated by holography, and it was used in the mask of ion etching. The groovy depth of the etched glass grating was 1.6μm. The glass waveguide was formed by K^+/Na^+ ion exchanging. The laser beam of 633nm was coupled in the waveguide by a prism at one end, then, it passed through the grating and came out of the waveguide at other end. In the experiment, the Bragg diffraction with several orders was observed. The first order Bragg diffraction had the highest efficiency of 90 percent.

A NEW METHOD TO DETERMINE THE R-CURVE OF CERAMICS-FRACTURE GRATING METHOD

The etching technique of the single-lined zero-thickness specimen grating is applied to the surface of the SiC fiber toughening Si3N4 ceramic composite specimen. The position of the crack and the crack length during the process of crack extension when the load is applied and gradually increased can be determined by recording the output voltage value of the Wheatstone bridge in which the ceramic specimen with the fracture grating on is located. The crack-growth-resistance(R-curve) of this material is thus obtained.

Cladding Modified Fiber Bragg Grating for Copper Ions Detection

This paper reports a fiber Bragg grating(FBG)as a biosensor.The FBGs were etched using a chemical agent,namely,hydrofluoric acid(HF).This implies the removal of some part of the cladding layer.Consequently,the evanescent field propagating out of the core will be closer to the environ­ment and become more sensitive to the change in the surrounding.The proposed FBG sensor was utilized to detect toxic heavy metal ions aqueous medium namely,copper ions(Cu^(2+)).Two FBG sensors were etched with 20 and 40μm diameters and fabricated.The sensors were studied towards Cu^(2+)with different concentrations using wavelength shift as a result of the interaction between the evanescent field and copper ions.The FBG sensors showed a good response in terms of significant wavelength shift in corresponding to varying Cu2+concentrations when immersed in aqueous mediums.The sensors exhibited excellent repeatability towards Cu ions.The results demonstrate that the smaller FBG etching diameter,the better optical response in terms of wavelength and linearity.

小闪耀角单晶硅光栅结构参数优化及制备工艺

本文开展了对单晶硅小闪耀角光栅的各向异性湿法刻蚀制备工艺研究,制备了适用于软X射线中波波段的闪耀光栅,以满足国家同步辐射光源的需要。首先,基于严格耦合波法对小闪耀角光栅进行了结构参数优化及工艺容差分析。在晶向对准过程中,先通过环形预刻蚀确定硅片晶向,再基于倍频调整法实现光栅掩模与单晶硅<111>晶向的对准。研究了光刻胶灰化技术及活性剂对光栅槽形质量的影响,并通过单晶硅各向异性湿法刻蚀工艺成功制备了接近于理想锯齿槽形的闪耀光栅。实验结果证明:所制备光栅闪耀角为1°,刻线密度为1200 gr/mm,闪耀面均方根粗糙度在0.5 nm以内。此方法可以应用于软X射线中波波段闪耀光栅的制作,在获得较高衍射效率的同时可以大大减少制作难度及成本。

GaAs基底上制备圆孔阵列光栅及其影响因素研究

为解决半导体激光器的偏振问题,提出了一种利用泰尔博特位移光刻曝光技术在Ga As衬底上制作周期光栅的方法,并系统研究了工艺参数和抗反射层对制备的周期光栅质量的影响。利用二次光刻工艺和反应离子蚀刻工艺在Ga As衬底上制备圆孔阵列周期光栅;通过电感耦合等离子体蚀刻设备制造均匀光栅。实验结果表明,该工艺流程可制备深度为20~150 nm的动态可调圆孔阵列周期光栅;当曝光剂量为30 m J·cm^(-2),曝光光强度为2 m W·cm^(-2),显影时间为1 min时,所曝光出的周期光栅符合实验要求;重复实验证明了利用泰尔伯特位移光刻技术制备光栅工艺的可行性及稳定性。

Spectral characterization of fiber Bragg grating with etched fiber cladding

A new method is presented to tune Bragg wavelength slightly by using hydrofluoric acid to etch fiber cladding.The spectral characteristics before and after etching and the change properties of Bragg wavelength are studied.Cladding modes are reduced during the etching process.High-order cladding modes are converted into radiation modes,and energy of cladding modes is coupled to the outside.As the cladding radius decreases,the Bragg wavelength shifts to longer direction.Experimental results show that this method can tune Bragg wavelength slightly,and the tunable range is 0.002-0.120 nm.

A flat-topped etched diffraction grating demultiplexer with low polarization-dependent loss using a tapered MMI structure

A flat-topped etched diffraction grating (EDG) demultiplexer with a low polarization-dependent loss (PDL) is designed. A design and simulation method based on the method of moment (MoM) is proposed. A 65-channcl EDG demultiplexer with channel spacing of 100 GHz is considered as a design example. A tapered multi-mode interferometer (MMI) is used to flatten the passband of the EDG demultiplexer. The numerical results show that the exit width of the tapered waveguide impacts the loss of the TE case more than that of the TM case. Based on this fact, the exit width of the taper is optimized to obtain the lowest PDL. The tapering angle is also optimized where the minimal ripple is obtained. The designed EDG demultiplexer has an excellent flat-topped spectral response and a very low PDL.

Design and analysis of a mode-hop-free tunable laser based on etched diffraction grating

A novel semiconductor laser which can achieve mode-hop-free tuning is proposed. The device consists of an etched diffraction grating （EDG） as a dispersive element to provide the mode selection function and an active waveguide to provide optical gain for the laser. The slab waveguide region of the EDG contains a tuning section covered by an electrode to inject a tuning current, and thus changes the refractive index. Mode-hop-free tuning is achieved by specially designing the shape of the tuning section, so that the tuning rate of the central wavelength reflected by the EDG and the tuning rate of the resonant wavelength of the laser cavity are equal. An optimized tuning section shape is designed to obtain the largest tuning range within a limited current range. Numerical simulation is presented to demonstTate the mode-hop-free tuning operation.

用于AR显示技术的亚波长Al光栅的ICP刻蚀工艺研究

铝材料因其良好的光反射率和低热线性膨胀系数,被广泛应用在增强现实设备的光栅光波导中。采用ULVAC公司生产的电感耦合等离子体(ICP)刻蚀设备NE-550对Al材料进行了干法刻蚀工艺的研究。实验中采用SiO_(2)作为刻蚀掩膜,Cl_(2)/BCl_(3)气体作为工艺气体,通过对实验工艺参数的调整,探究了ICP源功率、射频偏压功率、腔体压强以及气体流量对Al的刻蚀速率、与上层掩膜的选择比的影响。最后通过优化工艺参数,得到了底部平整、侧壁垂直的栅槽结构。此研究为亚波长尺度的光栅刻蚀工艺的优化和技术突破提供了参考。

宽波段全息-离子束刻蚀光栅的设计及工艺

设计和制作了一种在同一基底上具有多闪耀角的宽波段全息-离子束刻蚀光栅。提出了组合形成宽波段全息-离子束刻蚀光栅的分区设计方法,优化了3种闪耀角混合的宽波段全息光栅设计参数,并利用反应离子束刻蚀装置对该光刻胶掩模进行刻蚀图形转移,采用分段、分步离子束刻蚀技术开展了获得不同闪耀角的离子束刻蚀实验。最后在同一光栅基底上分区制作了位相相同,并具有9,18,29°3个不同闪耀角,口径为60mm×60mm,使用波段为200~900nm的宽波段全息光栅。衍射效率测试结果显示其在使用波段的最低衍射效率超过30%,最高衍射效率超过50%,实验结果与理论计算结果基本符合。与其它方式制作的宽波段光栅相比,采用宽波段全息-离子束刻蚀光栅不但工艺成熟,易于控制光栅槽形,而且光栅有效面积尺寸较大,便于批量复制。

紫外全息闪耀光栅的制作

通过理论计算研究了影响闪耀光栅衍射效率的因素,并利用离子束刻蚀模拟程序模拟刻蚀闪耀光栅来确定闪耀光栅的制作参数。以理论计算的闪耀光栅参数为依据,以刻蚀模拟程序为指导,基于全息-离子束刻蚀工艺制作了闪耀波长分别为250nm和330nm,光栅尺寸分别为85mm×85mm,60mm×60mm,线密度均为1200lp/mm的闪耀光栅。第一种光栅闪耀角为8.54°,非闪耀角为72°,其250nm波长自准直入射时的-1级衍射光衍射效率约为81%;第二种光栅闪耀角为11.68°,非闪耀角为74°,330nm波长自准直入射时的-1级衍射光衍射效率约为80%。实验结果表明,提出的方法可以在制作闪耀光栅的过程中实现对闪耀角的精确控制,获得的实验结果与理论计算结果符合较好。利用该方法能够在大尺寸基底上获得衍射效率>75%的紫外闪耀光栅。

闪耀全息光栅离子束刻蚀工艺模拟及实验验证

依据特征曲线法推导了非晶体表面的离子束刻蚀模拟方程,结合全息光栅的刻蚀特点开发出离子束刻蚀模拟程序,并通过实验数据分析并优化了非晶体材料刻蚀速率与离子束入射角的关系方程,最后利用离子束刻蚀实验对所开发的离子束刻蚀模拟程序进行了实验验证。调节掩模与基底材料的刻蚀速率比为2∶1至1∶2,制作了线密度为1 200l/mm,闪耀角为～8.6°,非闪耀角为34°～98°的4种闪耀光栅,与刻蚀模拟程序的结果进行对比,模拟误差<5%;控制离子束刻蚀时间为6～14min,制作了线密度为1 200l/mm,闪耀角为～8.6°,顶角平台横向尺寸为0～211nm的6种光栅,与刻蚀模拟程序的模拟结果进行对比,模拟误差<1%。比较实验及离子束刻蚀模拟结果表明,离子束刻蚀模拟程序获得的模拟刻蚀轮廓曲线与实际刻蚀轮廓曲线的误差<5%;模拟刻蚀截止点与实际刻蚀截止点误差<1%。实验表明,提出的模拟方程可以准确地描述不同工艺过程和工艺参数对最终刻蚀结果的影响,进而可预知和控制离子束刻蚀过程。

同步辐射球面闪耀光栅的研制

A spherical blazed grating (SBG) of 1200l/mm was successfully fabricated for the Seya Namioka monochromator of photochemistry experiment station at National Synchrotron Radiation Laboratory with the holographic ion beam technique. In addition to the general process, the photoresist ashing technique is developed for achieving good quality gratings.

窄光谱带宽X射线刻蚀多层膜光栅

结合X射线荧光分析和同步辐射单色器对窄光谱带宽多层膜的需求,开展了窄光谱带宽刻蚀多层膜光栅的理论和实验研究。用平均密度法从理论上阐明将多层膜刻蚀成不同刻蚀比的多层膜光栅后,光谱分辨率将得到提高。用磁控溅射方法制备了W/C多层膜,并用常规的光刻工艺对其进行刻蚀,得到了刻蚀后的多层膜光栅。掠入射X射线衍射测量表明,刻蚀后多层膜的衍射峰位置向小角方向移动,多层膜光栅没有改变剩余多层膜的结构,而且带宽减小,光谱分辨率得到提高,说明实验采用的工艺方法和工艺路线可以满足制作窄光谱带宽刻蚀多层膜光栅的要求,为今后进一步研究实用化元件打下了基础。

同步辐射Laminar光栅的研制

采用全息离子束刻蚀和反应离子刻蚀相结合的新工艺 ,在熔石英基片上成功地刻蚀出 2 0 0l/mm、线空比 4:6、槽深 70nm、刻划面积 60× 2 0mm2 的浅槽矩形Laminar光栅。对改进光栅线条粗糙度和线空比的方法进行了系统的研究。这一新工艺相对简单 。

大尺寸衍射光学元件的扫描离子束刻蚀

总结了大尺寸衍射光学元件离子束刻蚀技术的研究进展。针对自行研制的KZ-400离子束刻蚀装置,提出了组合石墨束阑结构和多位置分步刻蚀策略来提高离子束刻蚀深度的均匀性,目前在450mm尺寸内的刻蚀深度均匀性最高可达±1%。建立了针对多层介质膜光栅的衍射强度一维空间分布在线检测系统以及用于透射衍射光学元件离子束刻蚀深度的等厚干涉在线检测系统,实现了对大尺寸衍射光学元件离子束刻蚀终点的定量、科学控制,提高了元件离子束刻蚀工艺的成功率。利用上述技术,成功研制出一系列尺寸的多层介质膜光栅、光束采样光栅、色分离光栅以及同步辐射光栅等多种衍射光学元件。

用于1m Seya-Namioka单色仪的1200lp/mm Laminar光栅

针对国家同步辐射实验室燃烧与火焰实验站中1mSeya-Namioka单色仪对光栅的需求,采用全息离子束刻蚀工艺制作了1 200lp/mm Laminar光栅。首先,通过光刻胶灰化技术调节光刻胶光栅掩模占空比,在理论设计的误差允许范围内,对此光栅掩模进行扫描离子束刻蚀;然后,将光栅图形转移到光栅基底中去除残余光刻胶;最后,采用离子束溅射法镀制厚约40nm的金反射膜,采用热蒸发法镀制厚约60nm的铝反射膜。用原子力显微镜分析光栅微结构,结果显示光栅槽深为40nm,占空比为0.45。同步辐射在线波长扫描测试结果表明,镀铝光栅效率明显高于镀金光栅,获得的实验结果与理论计算结果基本符合。镀金光栅已替代进口光栅在线使用3年,其寿命大大超过复制光栅,基本满足了燃烧实验站的实验研究需求。

用于分频的闪耀光栅设计及衍射行为研究

详细地介绍了用于分频的闪耀光栅设计方法 ;推导了影响元件性能的衍射效率公式 ;并研究了纵横向工艺误差对其衍射行为的影响。模拟结果显示在 8%和 5%纵横向相对误差范围内 ,该闪耀光栅具有良好的分色效果。

一种基于啁啾光纤光栅温度不敏感的应力传感器

提出了一种基于啁啾光纤光栅温度不敏感的应力传感器。这种传感器是以腐蚀后啁啾的Bragg光纤光栅为敏感元件,利用光栅反射功率的变化测量应力的变化,反射功率对温度是不敏感的。利用光功率计检测光栅反射功率的变化。

纳米压印制作半导体激光器的分布反馈光栅

分布反馈(DFB)光栅的制作是半导体激光器芯片的关键工艺,通过纳米压印技术在InP基片表面涂覆的光刻胶上压印出DFB光栅图形,并分别通过湿法腐蚀和干法刻蚀技术将光栅图形转移到InP基片上。所制作的DFB光栅周期为240nm(对应于1 550nm波长的DFB激光器),光栅中间具有λ/4相移结构。采用纳米压印技术制作的DFB光栅相对于通常双光束干涉法制作的光栅具有更好的均匀性以及更低的线条粗糙度,而且解决了双光束干涉法无法制作非均匀光栅的技术难题。相对于电子束直写光刻法,采用纳米压印技术制作DFB光栅具有快速与低成本的优势。采用纳米压印技术在InP基片上成功制作具有相移结构的DFB光栅,为进一步进行低成本高性能的半导体激光器芯片的制作奠定了良好基础。