【作者】 姜俊英；

【导师】 张爱玲；

【作者基本信息】 天津理工大学 ， 通信与信息系统， 2012， 硕士

【摘要】 本文主要研究了基于相移光栅的双波长窄线宽光纤激光器的设计，其中双波长、窄线宽滤波的实现，以及激光器结构的设计是研究的重点。从等效谐振腔驻波条件的角度，对相移光纤光栅特别是双相移点光纤光栅以及相移取样光纤光栅的结构特点以及反射谱特性进行了一系列的理论研究。此外，实验研究了两种基于相移光栅的光纤激光器结构，并获得了激光输出。主要研究内容包括：(1)根据光纤光栅的耦合模理论和传输矩阵理论，结合单相移点光纤光栅中两段Bragg光栅的反射系数的相位特性，利用等效谐振腔的驻波条件，分析了影响单相移点光纤光栅透射波长的因素，分析表明：在光纤光栅中插入一个相移点，会在光栅的反射带宽内产生一个透射峰，透射峰的波长与单相移点的大小及位置有关。当相移量为π时，相移光栅透射峰波长只与相移量的大小有关，与相移点的位置无关；当相移量远离π时，相移光栅透射峰波长不仅与相移量的大小有关，还与相移点的位置有关。(2)利用等效谐振腔的驻波条件，对双相移点光纤光栅的反射谱特性及影响透射波长的因素进行分析。结果表明：在光纤光栅中插入两个相移点，会在反射带宽内产生两个透射峰。两透射峰的波长间隔与相移量的大小及相移点的位置有关。相移量一定时，波长间隔随着相移点间距变大而减小；当相移点间距一定，波长间隔随两相移点相位差的增加而增大，另外相移点间距越大，相移量对波长间隔的影响越明显。(3)通过设置合适的参数，取样光纤光栅可以得到具有双波长的反射谱，在该取样光栅中增加相移点，可以在原双反射带宽内分别得到超窄带的透射峰。同样利用等效谐振腔的驻波条件，对影响相移取样光栅透射波长的因素进行研究，可得：相移取样光栅的透射波长与相移点的位置及相移量的大小有关。改变相移量的大小，两透射波长会同时向短波长或长波长方向移动。相移点越偏离中点，相移量的大小对透射峰波长的影响越明显，但相移点远离光栅中点时，相移取样光栅透射功率损耗较大。(4)实验研究了两种不同的基于相移光栅的光纤激光器：1、等效为相移光栅的光纤对直接刻写在铒纤上，构造单相移点光纤光栅DFB光纤激光器，获得了稳定的单波长激光激射。2、相移光栅与Bragg光栅共同作为双波长窄带滤波器，构造双波长环形光纤激光器，得到双波长激光输出。更多还原

【Abstract】 In this thesis, the Dual-wavelength fiber laser with narrow linewidth based on thephase-shifted grating was designed. The focuses were how to obtain a dual-wavelength andnarrow line width filter and how to design the structure of the fiber laser. Standing wavecondition of the equivalent resonator, as a new method, was used to discuss the structure andreflection spectrum characteristics of phase-shifted grating, including the single anddual-phase-shift grating and the phase-shifted sampled grating. Laser with narrow linewidthbased on different laser structures can be obtained experimentally. The details were describedas follows:(1) Phase-shifted grating was regard as a resonator formed by two FBGs. According to thecouple mode and transfer matrix theory, combined with phase changes caused byreflection coefficient of the FBG, using standing wave condition of the equivalentresonator, transmission peak wavelength dependence of factors were analyzed. Thefollows can be demonstrated: there were one transmission peak in the bandwidth of thereflection; the wavelength space was influenced by value and position of the phase shift.when the phase shift was π, the transmission wavelength was not related to the positionof the phase shift, when the value of phase shift was deviated from π, the wavelength ofthe transmission peak was not only related to the value of phase shift, but also theposition of phase shift.(2) Using standing wave condition of the equivalent resonator, structural of the dual-phase-shifted grating and factors affecting transmission wavelength were analyzed, Thefollows can be demonstrated: there were two transmission peaks in the bandwidth of thereflection, the wavelength space was influenced by value and position of the phase shift.When the value of the phase shift was unchangeable, the wavelength spacing becamesmaller with the increasing distance of the two phase shifts. With invariable distance ofthe two phase shifts, the wavelength spacing became bigger with the increasing of phasedifference. With the increasing of distance between phase shifts, the value of the phaseshift impact on the wavelength space was more obvious.(3) With appropriately parameters, dual-wavelength reflection peaks in the reflection of thesampled grating can be obtained. When Phase shift was inserted, two new transmissionpeaks can be gained separately in the bandwidth of the two reflection peaks. Accordingto standing wave condition, transmission wavelength dependence of factors weredemonstrated: the transmission wavelength was related to the value and position of thephase shift. When value of the phase shift changed, both the transmission wavelengthsbecame bigger or smaller；With phase shift position deviated from the center, phaseshifted sampled grating has a more obvious wavelength change versus the value of phase shift, but there will be a high loss.(4) Two different kinds of fiber laser were studied experimentally:1. Grating pair wascarved on the EDF, due to the EDF between the pair can be regarded as phase shift, asingle phase shifted DFB fiber laser can be obtained. Single-wavelength narrowlinewidth laser was carried out.2. Dual-phase-shifted grating and FBG were used as thefilter, a dual-wavelength ring fiber laser was made up, dual-wavelength laser was carriedout.更多还原