Reach On Random Distributed Feedback Laser Based On Artificially Controlled Backscattering Fiber

Random distributed feedback fiber lasers base on the Raman amplification and random distributed Rayleigh Backscattering and have no cavity.The researches of the random distributed feedback fiber lasers have profound impact for nonlinear fiber optics,optical fiber laser,distributed optical fiber sensor,optical fiber communication and so on.It also provides a new research field for laser physics,nonlinear optics,optical fiber laser and so on.However,random distributed feedback fiber lasers usually need dozens or even hundreds of kilometers of feedback fiber due to the fiber loss and Rayleigh Backscattering coefficient is very small.In order to reduce the length of the feedback fiber,the paper proposed fabricating the reflectors in the single-mode fiber and the erbium-doped fiber by femtosecond laser micromachining technology.On the one hand,the artificially controllable reflectors are fabricated on the single-mode fiber core to enhance the feedback,which instead of random distributed Rayleigh Backscattering.On the other hand,the artificially controllable reflectors are fabricated on the erbium-doped fiber to instead of the feedback of the optical grating array.Finally,the artificially controllable feedback optical fiber serve as the feedback fiber to consist of random optical fiber laser that the structure is controllable.The research contents of the paper include three parts:1.First of all,if one reflector was fabricated per unit length of single-mode fiber,we simulated the reflected power per unit length of fabrication fiber according to the Rayleigh backscattering theory of the single-mode fiber.The feasibility of this method has also been analyzed.2.Secondly,the experiment setup is introduced.The Optical Time Domain Reflectometer(OTDR)system was used to real-time monitor the backscattering track of the fabrication fiber,of which the optimized fabricating parameters were studied.According to the research results of the optimized fabricating parameters,the artificial controllable feedback optical fiber,which has higher backscattering,was fabricated on the single-mode optical fiber and erbium-doped fiber.3.Finally,the random lasers of half open cavity based on the single-mode fiber and erbium-doped fiber of the artificial controllable feedback have been proposed.In the proposed laser,the gain of pumped erbium-doped fiber instead of the stimulated Raman scattering gain,the feedback was provided by the artificial controllable feedback optical fiber,and the FBG of center wavelength at 1530 nm was the filter.As the artificial controllable reflectors were fabricated in the single-mode fiber,the random laser based on the artificial controllable feedback single-mode fiber has reduced the length of feedback optical fiber to a few hundred meters.As the artificial controllable reflectors were introduced in the erbium-doped fiber,the feedback of reflectors instead of the grating array and the stable laser output was also obtained.The random distributed feedback laser based on artificially controlled backscattering fiber improved the structure complexity of the traditional random distributed feedback fiber laser.