预写入标尺实现光纤光栅布拉格波长精确控制  

Precise Control of Fiber Blagg Grating Wavelength by Preinscription Grating

作　　者：庄炜[1,2] 辛璟焘[1,2] 张旭 李红[1,2] 祝连庆[1,2] Zhuang Wei;Xin Jingtao;Zhang Xu;Li Hong;Zhu Lianqing(Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument,Beijing Information Science&Technology University,Beijing 100192,China;Beijing Laboratory of Optical Fiber Sensing and System,Beijing Information Science&Technology University,Beijing 100016,China;Beijing Key Laboratory of Optoelectronic Measurement Technology,Beijing Information Science&Technology University,Beijing 100192,China)

机构地区：[1]北京信息科技大学光电测试技术及仪器教育部重点实验室,北京100192 [2]北京信息科技大学光纤传感与系统北京实验室,北京100016 [3]北京信息科技大学北京市光电测试技术重点实验室,北京100192

出　　处：《中国激光》2022年第6期93-99,共7页Chinese Journal of Lasers

摘　　要：为提高光纤布拉格光栅(FBG)中心波长的刻写精度,提出了一种基于预写入标尺的FBG波长控制方法,并建立了预写入标尺波长与目标波长之间的关系。预写入标尺指的是在正式刻写指定波长(λ;)的FBG前预先刻写的弱FBG。首先,使用单个低能脉冲照射受一定预紧力作用的光纤,使之形成一个微弱但可测得反射峰的弱FBG,其反射中心波长为λ;接着撤去预紧力,测得松弛后的弱FBG的反射中心波长为λ;然后根据FBG中心波长漂移与受力大小的变化关系计算得到λ;,改变预紧力使FBG的反射波长变为λ;最后用高能量脉冲完成FBG的刻写,此时,松弛后的FBG的反射中心波长应为指定波长λ;。用预写入标尺法刻写了6种不同波长的FBG,FBG中心波长的刻写值与理论值的一致性较好,FBG刻写波长的误差均值为0.007nm,误差标准差为0.029nm。此方法实施简单,稳定可靠,能有效提高FBG中心波长的刻写精度。Objective Fiber Bragg grating(FBG)has become an essential optical filter component.Higher requirements for the accuracy of FBG wavelength are demanded when dealing with applications such as multiwavelength lasers,dense wavelength division multiplexing,and dense sensor arrays.Based on this,people developed several methods to obtain an accurate FBG.For example,different weights are hung at the termination of the optical fiber to apply different tensions,thus changing the inscribed wavelength with the same phase mask,which can also be altered by hanging weight during stress annealing,or using a dynamometer to control the preload of the fiber after calibrating the relationship between different preload and the inscribed wavelength.The methods mentioned above all apply indirect measurements to control the inscribed wavelength,thus introducing an additional source of error and limiting further improvements of inscribing accuracy.In this study,we design and construct a precise FBG Bragg wavelength controlling method based on preinscription grating using a 248nm excimer laser FBG inscribed system.Additional errors are reduced by directly monitoring the wavelength change.We demonstrate the usefulness of this method,which is simple,stable,and reliable and can effectively improve FBG center wavelength inscribing accuracy.Methods The specific inscribing process is shown as follows:1)Strip the coating layer to obtain a 10 mm long bare optical fiber and connect both ends to the optical fiber writing online monitoring system.2)Install the optical fiber to the positioning system and then apply a slight preload to enable the optical fiber to straighten.3)Control the excimer-pulsed ultraviolet laser in order for it to output a single pulse with the minimum output energy(30mJ)to preinscribe the optical fiber.A preinscribed grating with a weak reflection peak can be obtained with a Bragg wavelength ofλBr0.4)Remove the optical fiber from the positioning system and keep it slack.Here,the measured reflection center wavelength of prein

关 键 词：光栅 准分子激光 预写入标尺 波长控制 

分 类 号：TN305.7[电子电信—物理电子学] TH253[机械工程—机械制造及自动化]