Dual-frequency shift leads to chaos and beating in an erbium-doped fiber laser

Abstract

We present a dual-frequency shift scheme to produce chaos and beating in an erbium-doped fiber laser while we give this laser physics model including a photo attenuator absorbing the photon, where the absorption frequency of the photo attenuator can be shifted, and a pump modulator shifting the modulation frequency. It can be found that the modulated laser produces chaos, beating, and a lot of quasi-periodic states when both pump level and photo absorption of the laser are modulated by the attenuator and the modulator. Our numerical result illustrates a route to chaos or away from chaos after beating or quasi-period by shifting the pump modulation frequencies and the absorption frequencies of the attenuator while a dual-cycle, a cycle-3, a cycle-4, quasi-cycle, beating and chaos occurs in the modulated laser. We discuss the effects of two frequencies of the attenuator and the modulator on dynamics. And we find the chaos distribution with frequency variations of the absorption. It can be found that two frequencies of the absorption and the modulation guide the dynamics of the modulated laser. The result has great referenced values to laser, optics, and chaos.