Quasi-periodic route to chaos in erbium-doped fibre laser

Design and performance analysis of a tunable and self-pulsation diode pumped double-clad D-shaped Yb3+-doped silica fiber laser

“…Figure 8 also shows the strong regularity in the pulses. The laser output becomes quasi-CW for sufficiently high pumping rates as previously described in experimental and theoretical studies [8,9,13,25]. This is shown in Figure 9, in which the pumping power is 5 W, the laser power is 110 mW and the pulse repetition rate is now around 100 kHz.…”

“…This long lifetime implies that ESA from the upper laser level to a higher lying level ( 2 F 5/2 ) can occur and therefore has to be included in the model. In previous analyses of Yb 3+ -ion-pair effect [9], the ratio of emission to absorption cross sections (defined as γ in the following) was assumed to be γ = 1. In the following, we will show that the Yb 3+ -ion-pair effect on laser dynamics depends largely on the emission to absorption ratio γ.…”

“…Self-pulsing behavior in the fiber laser has been variously reported to be due to the presence of ion-pairs or clusters [11,12], bidirectional propagation in ''high-loss cavity'' and Brillouin-scattering effects in the fiber laser [13]. Ion-pairs (or ion clusters) are appropriate for the theoretical explanation of the performances of both heavily doped ytterbium-fiber amplifiers or superfluorescent fiber sources and self-pulsing instability observed in ytterbium-doped fiber lasers (YDFLs) at λ=1070nm [3,[8][9][10]13]. It was demonstrated [14] that for low ion-pair concentrations (x<5%) the EDFL operates continuously, where x is the proportion of ion-pairs in the doped fiber, whereas for high ion-pair concentration (x≥5%) the laser is self-pulsing.…”

“…Obviously, the quenching effect is negligible for low ion-pair concentrations allowing CW operation of the YDFL. On the other hand, for high ion-pair concentrations an efficient saturable absorption effect occurs leading to self-pulsing behavior [9]. The relaxation oscillations that are present in the output of a high-power free-running diode-pumped Yb 3+ -doped silica fiber laser has been characterized and modeled [16].…”

“…A ytterbium-doped fibre laser with a unidirectional ring cavity containing a polarizer placed between two in-line polarization controllers is presented, depending on an equivalent saturable absorber, this laser operates in continuous, Qswitched mode-locked or CW mode-locked regimes [5] or pump modulation conditions [6]. In spite of their highly longitudinal multimode operation due to the large inhomogeneous line width, fiber lasers exhibit cooperative effects between longitudinal modes; this enables simple modeling of the dynamics by low dimensional equations [7][8][9]. Beside their evident practical applications, fiber lasers are very interesting from a basic physics perspective.…”