In this work , based on the threshold condition of the fiber grating external cavity semiconductor laser ( fgesl ) which the phase of the fiber grating has been included , the effect of the temperature variation and the fg external cavity length on the lasing wavelength of the fgesl has been investigated theoretically . in addition , we have used the phase condition of fgesl to get the longitudinal mode distribution of fgesl , then the influence of the injected current on the output characteristics of fgesl has been studied 基于此，本文中利用阳实际的反射相位分布，计及半导体激光器( ld ) 、外腔及光纤光栅( fg )三者的共同作用，根据fgesl满足的闽值条件，从理论上研究了温度及外腔长度的变化对fgesl激射波长的影响;根据fgesl中纵模所满足的相位条件得到其纵模分布后，利用fgesl满足的多模速率方程，研究了ld的注入电流对fgesl输出特性的影响。
Vertical - cavity surface - emitting lasers ( vcsel ' s ) have distinct advantages over conventional edge emitting lasers , such as small divergence angle , single longitudinal mode operation and very low threshold current . they are especially suitable for making two - dimensional ( 2 - d ) arrays as well as vcsel ' s based integrate devices 垂直腔面发射半导体激光器( vcsel )与传统的边发射半导体激光器相比，它具有发散角小、单纵模工作、非常低的阈值电流等优点，尤其它适于二维面阵集成和与其它光电子器件集成。
Numerical simulations show that : ( 1 ) owing to the temperature variation resulting in the change of the refractive index of both the semiconductor medium and the fi ber , and further inducing the shift of the longitudinal modes of the fgesl , the lasing wavelength of the fgesl has a shift tendency to longer wavelengths with the increase of the temperature ; the mode hopping happens for a short external cavity and disappears for a long external cavity 数值模拟的结果表明:由于温度变化造成半导体介质和光纤的折射率发生变化从而导致fgesl的纵模发生移动，因此fgesl的激射波长随着温度的升高将存在向长波长方向发生移动的趋势，对于短外腔， fgesl的纵模间距较大，半导体介质折射率随温度的变化程度大于光纤折射率随温度的变化程度，因而存在模式跳跃现象;对于长外腔，由子fgesl的纵模间隔很小，因而不存在明显的模式跳跃现象。
According to the guidline , two nd : yag lasers have been designed and set up , one is end - pumped by lower output power ld using a selfoc micro lens , and the other is end - pumped by high output power ld using a pair of lenses are designed , and the characteristics such as output power and power stabilization of both solid - state lasers are investigated . thirdly , when an empty liquid crystal cell is inserted in the cavity of the nd : yag laser pumped by high power ld , the laser can operates in single axial mode . finally , according to the relationship between the laser output power and the longnitudinal a ld - end - pumped nd : yag laser sensor for displacement measurement has been investigated theoretically and demonstrated experimently , the results indicate that when the mean radius of pumping inside the laser cavity is far less than that of the oscilating laser mode , the exponential of the output power is a gauss function of the longitudinal positon of focused spot of ld pumping beam , both the measurement range and the sensitivity are dependent on the incident pumping power , as the incident pumping power is increased , the measurement range is enlarged and the sensitivity is improve d 本文首先介绍了ld泵浦nd ： yag激光器的发展状况、主要特性及其应用，从四能级速率方程出发，推导了ld泵浦nd ： yag激光器的阈值、输出功率和斜效率的表达式，并简述了激光器的工作原理、结构型式和倍频方法；其次，以空间相关的速率方程为基础，提出了ld端面泵浦nd ： yag激光器的设计方法，给出了一定泵浦耦合方式下，振荡光模尺寸、最佳输出耦合率、泵浦光模尺寸、泵浦光焦斑位置等参数的选取依据，以此为依据，设计了自聚焦透镜耦合小功率ld泵浦nd ： yag激光器和透镜组耦合高功率ld泵浦nd ： yag激光器，对激光器的输出功率和功率稳定性等特性进行了实验研究；再次，在带尾纤输出的高功率ld泵浦nd ： yag激光腔内插入一只空液晶盒，观察到了激光器以单纵模运转；最后，根据泵浦光焦斑端面位置对激光输出功率的影响规律，提出了ld端面泵浦nd ： yag激光位移传感新方法，并进行了理论和实验研究，研究结果表明：当激光晶体内泵浦光平均光斑半径远小于振西安理工大学硕士学位论文荡光束腰半径时，激光输出功率的自然指数与泵浦光焦斑的纵向位置成高斯变化规律，测量范围和灵敏度依赖于泵浦功率，随着泵浦功率的增加，测量范围扩大，灵敏度提高，当端面泵浦功率为7 . 24w (最大输出功率为1 . 926w )时，激光位移传感器的测量范围和灵敏度分别是13 . 045mm和0 . 148mw / pm 。
Realizing the excellency of nd : yv04 crystal , we use nd : yv04 / ktp firstly in our experimentation . the loss of light with different polarized orientation is different , when it through nd : yv04 crystal . utilizing the case and changing the thickness of ktp crystal by controlling temperature , we get a narrow light filter , so the cavity operates with single longitudinal mode 文中提出一种新的方案，采用nd ： yvo _ 4 ktp组合，利用nd ： yvo _ 4晶体对偏振态的选择作用以及温度控制ktp晶体长度，实现双折射窄带滤波，强制激光器工作在单纵模的模式下。
The principle advantages of vcsels over conventional edge - emitting lasers lie in ultralow threshold current , small far - field divergent angle , high modulation frequency , potential for wafer level testing and the ease for single longitudinal mode operation and two - dimension integration . as a result they show considerable promise for applications such as optical fiber communication , parallel optical interconnects , optical information processing and neural networks , etc . a direct coupling theoretical model in quasi - three - dimension for the gain - wave guide vertical - cavity surface - emitting lasers has been created in this paper 它与传统的边发射激光器相比具有更优越的特性，例如，具有极低的阈值、较小的远场发散角、调制频率高、易实现单纵模工作和二维集成，无须解理封装即可进行在片测试等，所以，它被广泛应用于光纤通讯、并行光互联、光信息处理、光神经网络等领域。
The stability output second harmonic generation ( shg ) experiment results of single - longitudinal mode and multi - longitudinal mode with long cavity were explained reasonably with these rate equations . the high polarization of fundamental wave in the isotropic laser media nd : yag with type - i critical phase - matching lbo was studied with the rate equations including polarization of fundamental light . using the polarization function of lbo , a quartz full - wave plate was introduced into the cavity , a kind of birefringent filter by considering the combination of the polarization function of the type - i critical phase - matching doubling frequency crystal lbo and the quartz whole - wave plate was constructed 将腔内多纵模倍频速率方程推广应用到准三能级蓝光激光器中，分析了一个纵模、两个纵模、多个纵模时的噪声情况，合理地解释了实验中激光器单纵模运转以及长腔多纵模运转时稳定输出的实验现象，同时利用该速率方程分析了以各向同性激光晶体nd : yag为工作物质，类临界相位匹配lbo为倍频晶体的蓝光激光器中基频光偏振特性，合理利用类临界相位匹配lbo倍频晶体的偏振特性与引入的石英晶体全波片构成双折射滤光片，通过选单频来抑制噪声，获得了蓝光低噪声的稳定输出。
The compensator compensates the change of polarized light , and also controls the polarized orientation . in result , we get a cavity , with the orientations of the linear polarized multi - longitudinal modes are agree . the noise of green output reducing , the cavity is steady with multi - longitudinal modes operating 本文首次将nd ： yvo _ 4晶体应用于抑制激光噪声的补偿片法中，利用nd ： yvo _ 4晶体的线偏振特性，控制谐振腔内激光束的偏振方向，使多纵模均为线偏振，且偏振方向一致，从而减少了绿光输出中的波动现象。
As a method to obtain higher sbs reflectivity by improving the monochromaticity of laser system , the ld end - pumped pulse - microchip laser operated on high - repetition and single - frequency has also been researched . in section v , we revised the previous theoretical model for passive - q - switched laser using cr4 + : nd3 + : yag by introducing the space dependence between the photons and inversion populations in microchip resonator 由于泵浦激光的线宽对sbs反射率有显著影响，而利用单纵模、高重复频率运转的脉冲微片激光器作为dpl系统种子光源来提高激光系统单色性是一种可行的技术方案。
In this paper , a new theoretical model is established for optical fiber pumped by broadband laser . using the new model , we have analyzed the influence of longitudinal - mode number , bandwidth and line - width of pumping source on sbs reflectivity , and pointed out the monochromaticity of pumping laser has obvious affect on optical fiber conjugator 成功解释了激光线宽、纵模间隔与数目对光纤中sbs过程的影响，并通过数值计算分析了sbs阈值、反射率、相对稳定性、保真度等性能参数随着注入激光能量、脉宽以及光纤长度、芯径的变化趋势。
