The Fiber Grating And Its Application In High Power Fiber Laser

Fiber grating is one of the most rapid developed and widely used fiber passivecomponents, particularly play an important role in the fiber sensing and opticalcommunication. High power fiber laser as a new generation of laser is widely concerned forits advantages such as good heat dissipation, high conversion efficiency, low pumpingthreshold, good beam quality, low maintenance cost. The optical resonant cavity comprisedof fiber grating has an effect of resonant amplification and frequency selection on fiber laser,which is very meaningful for the all fiber structure of fiber laser, so the study of fiber gratingand its application in high power fiber laser is particularly important. In this thesis, the maintheoretical and experimental contents are as follows:(1) The development history and the state of research at home and abroad of fibergrating and its application in high power fiber laser are summarized. The practicalsignificance and approaches of this research are introduced.(2) Based on the transfer matrix method, the reflection characteristics of linear chirpedfiber grating (LCFG) and the transmission characteristics of F-P resonant cavity consisted ofa pair of LCFG are analyzed. Numerical analysis and simulation have been performed by theMATLAB.(3) A theoretical model of Yb3+doped double-clad fiber lasers (YDDCFLs) is presented.The performance of the YDDCFLs consisted of linear resonant cavity is obtained, thedependence of the performance of the YDDCFLs on the loss factor are analyzed andsimulated.(4) A Q-switched YDDCFLs is designed, through the experiment, the dependence of theperformance of the YDDCFLs such as threshold, output power, slope efficiency,self-oscillation point on the reflection bandwidth and matching degree of center wavelengthare analyzed, then reasonable explanations are presented.