E . , the carrier frequency of a gaussian beam deviates from the resonant frequency of a fabry - perot etalon ) , variations of the peak intensity , the position of the peak intensity and the dwdm systems , has received considerable attention . in this work , after taking into account the wavelength - depended reflectivity distribution profile of a fiber bragg grating , the oscillation wavelength # _ ( 1 ) of long external cavity fiber bragg grat 与共振情况(即高斯光束的载波频率与法布里一拍罗滤波器的谐振频率一致)相比,非共振条件(即高斯光束的载波频率与法布里一拍罗滤波器的谐振频率存在偏差)一透射光束的峰值强度、峰值强度所对应的位置、以及光斑的大小随入射角的变化都发生了显著的改变。