High-energy harmonic mode-locked 2 μm dissipative soliton fiber lasers

Abstract

High-pulse-energy harmonic mode-locking in 2 μm Tm-doped fiber lasers (TDFLs) is realized, for the first time, by using a short piece of anomalous dispersion gain fiber and the dissipative soliton mode-locking mechanism. Appropriately designing the cavity dispersion map and adjusting the cavity gain, stable harmonic mode-locking of the dissipative soliton TDFL from the 2nd to the 4th order is achieved, with the pulsing repetition rates and pulse energy being 43.4, 65.1, 86.8 MHz, and 6.27, 4.32 and 3.29 nJ, respectively. The harmonic laser pulse has a pulse width of ~30 ps and a center wavelength of ~1929 nm with a spectral bandwidth of ~3.26 nm, giving a highly chirped laser pulse. Two types of soliton molecules are also observed in this laser system.

Developing High-Energy Dissipative Soliton 2 μm Tm3+-Doped Fiber Lasers

“…Here, harmonic mode-locking transition was obtained through changing the intracavity gain, and different light intensity leaded to different pulse dynamics [64]. Harmonic mode-locking from the first to the fourth order was consecutively observed, as presented in Figure 12 [63]. Compared to the fundamental mode-locking, the pump power had to be increased to over 708 mW to achieve the higher-order harmonic mode-locking.…”

“…Schematic of the passively mode-locked thulium-doped fiber laser. WDM, wavelength division multiplexer; SMF, single-mode fiber; TDF, thulium-doped fiber; DCF, dispersion-compensating fiber; SESAM, semiconductor saturable absorber mirror [63]. and the fourth harmonics, but certain supermode noises were present for the second and the third harmonics.…”

“…Maximum single pulse energy and average output power of the 2 μm harmonic mode-locked fiber laser at several harmonic orders[63].…”

“…RF spectrum of the fiber laser for the (a) first-, (b) second-, (c) third-, and (d) fourth-order harmonics[63].…”

Switchable Dual-Wavelength Mode-Locking of Thulium-Doped Fiber Laser Based on SWNTs

“…Different from active mode-locking techniques, passive mode-locking is simple, compact and low-cost without using active modulator in the laser cavity. Generally, passively mode-locked thulium-doped fiber lasers (TDFLs) can be implemented by nonlinear polarization rotation (NPR) [3], nonlinear amplifying loop mirror (NALM) [4], nonlinear optical loop mirror (NOLM) [5], semiconductor saturable absorber mirror (SESAM) [6], graphene [7], topological insulator [8], and the combination of saturable absorber (SA) with nonlinear switching based techniques [9]. As carbon allotropes draw much attention recently, single-wall carbon nanotube (SWNT) has been demonstrated to possess ultrafast nonlinear optical responses [10].…”