The Multipeak Phenomena and Nonlinear Effects in ${Q}$-Switched Fiber Lasers

The Influence of Nonlinear Effects Upon Oscillation Regimes of Erbium-Doped Fiber Lasers

“…Actively Q-switched (AQS) EDFLs based on acousto-optics modulator (AOM), implemented in the Fabry-Perot geometry, usually produce Q-switch (QS) pulses with duration from a few to hundreds ns [1]. The QS pulses are normally composed of a few sub-pulses separated by round-trip time of photon inside the cavity [31,32]; this AQS regime will be called further "conventional" (CQS). In the meantime, it is known that in certain conditions FLs demonstrate stochastic QS pulsing, which stems, as it will be clearly demonstrated below, from intra-cavity stimulated Brillouin scattering (SBS) [33].…”

Controlling Actively Q-Switched Laser Output by Nonlinear State Feedback

“…Since the physical quantities y and x 2 are always non-negative for all time and K 5 < 0, the solution of [3] is bounded by the solution ofẋ 2 = K 3 + K 4x2 ,x 2 (0) = x 20 , which isx 2 (t) = x 20 e K 4 t + K 3 (e K 4 t − 1)/K 4 . Thus, the internal dynamics remain bounded at all time.…”

“…Q-switched fiber lasers are ideal candidates for optical signal generators since light is already coupled into the fiber. However, when fiber lasers are Q-switched, one often obtains complicated pulse shapes with multiple peaks (3). Thus, precise regulation of the output pulse shape would be a truly enabling technology for the application of fiber lasers in optical communications.…”

High energy in-band pumped erbium doped pulse fibre laser

“…The AOM was controlled by an arbitrary waveform generator (AWG) (HP 33120A). By changing the ramping rate of the trapezoidal electrical pulse, the optical rise time of the AOM can be increased to 500 ns, such that the multi-peak pulse phenomenon (MPP) can be eliminated [3]. This generated ~102-ns single-peak pulses with 13.5-μJ pulse energy as shown in …”

“…With the EYDF, a maximum pulse energy of 1.15-mJ had been reported with an M 2 of 1.65 and pulsewidth of 575 ns [2]. However, due to the uncontrolled multiple-peaks phenomenon (MPP) in the Q-switched seed source [3], the seed output pulse was temporally modulated. Thus, the initial 70-ns MPP pulse evolved into a 575-ns output pulse with even more sub-structures.…”