Study Pulse Parameters versus Cavity Length for Both Dispersion Regimes in FM Mode Locked

Bushra Razooky Mhdi,Basher R.Mhdi,Nahla A.Aljabar,Gaillan H.Abdullah

doi:10.11591/ijeei.v3i1.130

Abstract

To demonstrate the effect of changing cavity length for FM mode locked on pulse parameters and make comparison for both dispersion regime , a plot for each pulse parameter as Lr function are presented for normal and anomalous dispersion regimes. The analysis is based on the theoretical study and the results of numerical simulation using MATLAB. The effect of both normal and anomalous dispersion regimes on output pulses is investigate Fiber length effects on pulse parameters are investigated by driving the modulator into different values. A numerical solution for model equations using fourth-fifth order, Runge-Kutta method is performed through MATLAB 7.0 program. Fiber length effect on pulse parameters is investigated by driving the modulator into different values of lengths. Result shows that, the output pulse width from the FM mode locked equals to τ= 501ns anomalous regime and τ=518ns in normal regime.

Highlights

Ultrashort optical pulses have great applications in fields such as ultrafast optics, optical fibre communication, optical measurement, micro-mechanism processing, and medical treatments [1]
To demonstrate the effect of changing cavity length on pulse parameters and make comparison for both dispersion regimes, a plot for each pulse parameter as Lr function is drawn in Figure 1 for normal and anomalous dispersion regimes
The main difference is that: in anomalous regime, the temporal shift is greater than normal regime by five times

Summary

Introduction

Ultrashort optical pulses have great applications in fields such as ultrafast optics, optical fibre communication, optical measurement, micro-mechanism processing, and medical treatments [1]. Compared with mode-locked solid-state lasers, ultrashort pulse fibre lasers have advantages of compactness, greater stability and so on. A novel all-normal-dispersion (ANDi) modelocked fibre laser, in which all components are of normal dispersion, has been proposed [6] In this diagram, the energy of output pulses can be much higher, [7,8,9,10] and designs can be greatly simplified especially for Yb-doped mode-locked fibre lasers whose operating wavelength is in the normal dispersion domain of common fibers. Yb3+ doped fibers have a broad emission bandwidth, large saturation fluence and high optical to optical conversion efficiency They form an excellent gain medium for the generation and amplification of ultrashort optical pulses in the 1μm wavelength range [11]. In the following all the terms of Mode-Locking master equation will be identified

Anomalous Regime

Results and Analysis

Conclusion