Tuning Bragg wavelength by writing gratings on prestrained fibers

Bragg gratings at a specific wavelength are made using an excimer KrF laser and a phase mask. The wavelength can be varied for fine tuning and multiplexing applications by straining the optical fiber during UV illumination. When the strain is removed, the grating formed is at a smaller wavelength than that dictated by the phase mask for the unstrained fiber. This technique was demonstrated by writing two gratings located at the same point in the optical fiber. The transmission from the first grating was used as a means for in situ absolute wavelength tuning. The second grating made with approximately 0.2% axial strain was at 1534.54 nm. Once the grating was made, the strain was removed from the fiber leaving the second grating tuned to 1532.04 nm, a wavelength shift of 2.5 nm     

Fiber Bragg grating fabrication for dispersion slope compensation

Group-delay dispersion slope causes signal deterioration in long-distance high-data-rate communication systems. We report the fabrication of high-quality apodized and chirped fiber gratings with dispersion slopes as high as -1800 ps/nm/sup -2/ over a 0.7-mn bandwidth-sufficient to compensate for the dispersion slope of >25000-km length of standard fiber at a wavelength of 1550 nm. We believe this is the first time that fiber Bragg gratings have been specifically designed and fabricated for dispersion slope compensation. The fabrication technique uses a standard unchirped phase mask and two scans of the inscribing UV beam.     

Long-phase error-free fiber Bragg gratings

Stitching errors in the phase mask degrade the spectral response of fiber Bragg gratings fabricated with the phase mask technique. We successfully fabricated a stitching error-free phase mask and applied it to the fabrication of fiber Bragg gratings (FBGs). The gratings have no observable excess sidelobes in the reflectivity and show excellent wavelength selectivity     

带状光纤多波长阵列光栅刻写工艺研究

为了实现一次性在八芯带纤上不同波长阵列光纤光栅刻写,采用专门设计的带纤夹具夹持光纤,使用电控位移平台对带状光纤整体施加拉力,利用相位掩膜工艺对光纤逐根曝光,采用扫描写入的方法进行汉明切趾,仅用单一相位模板就实现了八芯带纤上不同波长阵列布喇格光纤光栅刻写。刻栅过程由电脑编程控制,中心波长、波长间隔以及切趾方式可以灵活调整。结果表明,获得的光栅其3dB带宽为0.2nm、波长间隔为0.5nm、波长偏差小于50pm、反射率达到80%~85%。此种带状光纤多波长阵列光栅刻写工艺是完全可行的。     

Occurrence of Features of Fiber Bragg Grating Spectra Having a Wavelength Corresponding to the Phase Mask Periodicity

The use of a phase mask with 536 nm uniform pitch allowed the fabrication of a fiber Bragg grating for use at a Bragg wavelength of 785 nm. Reflection and transmission features at 1552 nm, twice the Bragg wavelength, associated with the phase mask periodicity were observed. However, when phase mask orders other than ＋1 were absent during fabrication the features at 1552 nm were not evident.     

利用动态相位掩膜板法制作光纤光栅

在相位掩膜板法光纤Bragg光栅(FBG)制作系统中,通过高精度陶瓷压电(PZT)促动器对相位掩膜板进行运动控制,实现对光栅折射率交流调制量和相位的任意调制,从而实现相移、切趾和啁啾等FBG的制作,从而提高FBG制作工艺的灵活性。     

Formation Technologies of Fiber Bragg Gratings

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Formation Technologies of Fiber Bragg Gratings

The principle of fiber Bragg gratings(FBG)is briefly described.The formation technologies of FBG are systematically given and analyzed.In addition,the experiment is described in detail,e.g.,the phase mask method is used to write directly the period Bragg gratings into the Ge-doped single mode fiber with KrF excimer UV laser.The results of experiment are also presented and analyzed.     

基于相位掩模板的常规光纤制备弱反射光栅

为了探索采用常规单模光纤制备弱反射光纤光栅的可行性,以降低材料成本和传输损耗,基于相位掩模板法,在常规单模光纤上刻制弱反射光纤布喇格光栅(WFBG),并进行了实验验证.建立相位掩模板刻栅系统光场统一方程,分析光场分布对光纤布喇格光栅(FBG)中心波长和反射率的影响;采用传输矩阵法分析相位掩模板长度、平均折射率变化对FB...     

248 nm KrF准分子激光零级抑制石英相位掩模器的研制

实验研制了针对波长２４８ｎｍＫｒＦ准分子激光的零级抑制石英相位掩模器。用双层掩蔽和图形转移技术，在双面抛光的石英基片上以ＣＨＦ３／Ｏ２为反应气体，用反应离子刻蚀技术制作了具有良好完整性、周期１．０８５μｍ的石英相位掩模器。实际测量表明其零级衍射效率被抑制到５．９７％。     

光纤布喇格光栅的制作技术

简单介绍了光纤布喇格光栅（ Ｆ Ｂ Ｇ） 的原理及光学特性,详细阐述了 Ｆ Ｂ Ｇ 的制作技术。此外,详细地描述了采用 Ｋｒ Ｆ 激光器,利用位相掩模法光刻光纤形成 Ｆ Ｂ Ｇ 的实验。此种方法与其他方法相比,有很多的优点。给出和分析了实验的结果     

8-wavelength DBR laser array fabricated with a single-step Bragggrating printing technique

An 8-wavelength distributed Bragg reflector (DBR) array for narrow channel wavelength division multiplexing (WDM) has been fabricated with a new technique for printing first-order Bragg gratings using a phase mask and a conventional incoherent source. All the distributed gratings were printed in a single photolithographic step with a slightly modified mask aligner. The DBR's excellent wavelength control for channels separated by as little as 0.8 nm is described. Many advanced photonic devices relying on gratings like quarter-wave shifted distributed feedback (DFB) lasers and wavelength division multiplexing (WDM) components can potentially be manufactured with this technique in a simple and cost-effective way     

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.     

多波长啁啾光纤光栅叠栅的数值分析和设计

为了研究多波长啁啾光纤光栅叠栅的反射和时延特性,提出多波长啁啾光纤光栅叠栅的耦合模理论方法,得到波长间隔Δλ=1.6nm的4波长和8波长的啁啾叠栅的反射谱和时延特性的数值分析结果,并设计了波长间隔Δλ=0.4nm的8波长的啁啾叠栅,数值分析结果与实验结果非常一致.结果表明,多波长啁啾光纤光栅叠栅的耦合模理论是可靠的,可用来分析其各种特性,此方法对多波长啁啾叠栅的设计和制作具有重要的参考价值.     

基于莫尔光纤光栅的带通滤波器

通过改变写入条件,控制两次曝光量、光纤拉伸大小和起始位相差等参数,可以调整π相移点的位置,制作出符合要求的相移光纤光栅.用同一块均匀相位板在普通的SMF-28单模光纤上制作出了3 dB带通宽度分别为0.01和0.5 nm的带通滤波器,符合理论模拟的计算结果.利用啁啾量为10 nm/cm,长度为1 cm的啁啾相位掩模板制作了7信道的带通滤波器.     

一种低成本FBG高温传感器的研究

采用相位掩模法,利用紫外光在载氢普通掺锗单模石英光纤中制作出光纤布拉格光栅(FBG)。同时,将反射率为17dB的光栅FBG1和反射率为41dB的光栅FBG2置于30～1000℃的高温炉内进行温度特性比较实验。在30～870℃范围内FBG1和FBG2两者中心波长随温度的变化趋势一致,且两个光栅反射波长都在870℃时消失,当温度继续升高到900℃时,仅有FBG2再次出现反射率为1dB的反射峰。对经过高温处理后的FBG2再次进行30～1000℃温度测量实验,温度灵敏度为0.02nm/℃,线性度为0.999。实验结果表明,对于具有高反射率的FBG进行高温热处理后,其可以在30～1000℃的温度范围内进行传感测量,且中心波长随温度变化呈良好的线性关系。利用该方法可以制作出低成本的可用于高温环境测量的FBG温度传感器。     

全光纤转动拉曼激光雷达的光纤光栅分光技术研究?

设计了一款由可见光波段的光纤布喇格光栅和光纤耦合器构建的全光纤转动拉曼激光雷达分光系统。利用相位掩模板侧向成功刻写530 nm波段光纤布喇格光栅,并初步测试其透射谱和反射谱性能。为提高光纤光栅中心波长与大气氮气分子转动拉曼谱线的匹配特性,利用悬臂梁设计高调谐灵敏度的调谐系统。实验结果表明,成功研制的可见光波段光纤布喇格光栅其反射率约为95%,带宽约为0.3 nm,应力调谐系统可实现± 0.6 nm范围18 pm/r 的波长调谐。     

Magnification of mask fabricated fibre Bragg gratings

Bragg gratings have been formed in optical fibres by diffraction of a phase mask. This technique is expanded by allowing for the possibility of shifting the Bragg wavelength for a fixed mask periodicity. This method uses a simple lens to introduce a curvature on to the wavefront of the diffracting light that results in a magnification of the original periodicity formed by the mask. The authors show experimentally that the Bragg wavelength is shifted to a shorter wavelength by the addition of a converging lens before the mask.<>     

基于重叠写入啁啾光栅的Fabry-Perot腔的研究

以两段重叠写入的啁啾光栅作为反射面,构成光纤光栅Fabry-Perot(FP)腔.分别采用施加应力法和移动相位掩模板法,在同一段光纤中重叠写入啁啾光栅形成FP腔.使用啁啾量为1 nm的相位掩模板进行实验,两种方法曝光后的重叠啁啾光栅都可以形成明显梳状透射光谱.使用移动相位掩模板法,透射光谱的自由光谱范围(FSR)可达0...     

基于游标原理的可调谐分布反射全光纤激光器

报道了一种新型全光纤离散可调谐分布反射(DBR)光纤激光器。光纤激光器为短腔结构,其有源区采用Er-Yb共掺单模光纤,有源光纤长度为6 cm。激光器采用两组级联光纤布拉格光栅(FBG)为反射腔镜,前腔镜各级联光纤布拉格光栅的布拉格波长间隔为1 nm,后腔镜为0.8 nm,利用游标原理,通过对前腔镜级联光纤布拉格光栅进行机械调谐,使前后腔镜各反射波长分别对准,实现了四个固定波长间隔为0.8 nm的离散调谐。这种光纤激光器具有波长调节准确,调谐速度快,成本低的优点,可用于作为多波长光纤传输系统的发射光源或系统检测光源,进一步增加级联光栅的组数可实现更大调谐范围。