الفهرس 
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Abstract
A random distributed feedback fiber laser (DFB-FL), with an apodized fiber Bragg grating (FBG) or an apodized Distributed Feedback Fiber (DFB) optical filter, is proposed. This leads to a narrow band light generation from the random DFB-FL optical source. This is a theoretical work depending on numerical analysis. Our proposed system consists of a random DFB-FL, with input pump power and long fiber length, followed by an optical filter. The filter has high reflectivity, high sidelobe suppression ratio (SLSR), and narrow full-width half-maximum (FWHM). A suitable apodization function is selected in order to improve the performance using the FBG/DFB optical filter. The performance of proposed system is evaluated by determining its reflectivity, SLSR, and FWHM over a 10, 50, 100, 150, and 200 km random DFB-FL and varying the pumping power from 1 W to 15 W. The reflectivity spectrum of the FBG or DFB filters is varying according to the variation of the modulation depth (no) and grating length (Lg). Most of the apodization profiles need 10-5 modulation depth and 10-20 mm grating length to provide narrow FWHM of 0.08 nm and large SLSR. Our results reveal that a FWHM of 0.08 nm with a high SLSR of 13 dB is achievable when using a uniform, and positive-tanh apodization profiles to obtain an output light spectral density of 1.47 W/nm for 15 W pumping power.