Analytic Technique For Active Mode-Locked Fiber Lasers

Abstract

In this work, Aِmplitude modulation mode-locked fiber laser isstudied,by using Ytterbium Doped Fiber Laser, single mode fiber,operating with 1055 nm wavelength with 976 nm optical pump and AMMode-Locked by optical modulators. A grating pair is used to compensatethe normal dispersion. The effect of both normal and anomalous dispersionregimes on output pulses are investigated. Master equation of the Modelockingfiber laser is introduced .Pulse shapes for both dispersion regimesare assumed after modifying (Ginzburg-Landu equation) GLE which isessentially Generalized Nonlinear Schrödinger equation GNLSE and byapplying the moment method ,a set of five rate equations for pulse energy,pulse width ,frequency shift ,temporally shift and chirp ,which solutionsdescribed the pulse from round trip to the next and how they approach tosteady state values. To solve these equations numerically fourth order,Runge-Kutta method is performed through Mat-Lab 7.0 computer program.Result shows that, the output pulse width from the AM mode-Lockedequals to τ=0.8ps in anomalous and τ=1ps in normal regimes. The studyshows the stability of working in anomalous dispersion regime is betterthan normal regime.

Keywords

• fiber laser
• ytterbium doped fiber
• am mode locking
• moment method
• pulse chirp
• pulse energy
• pulse width