Passively mode-locked fiber laser by a cell-type WS2 nanosheets saturable absorber

Abstract

A cell-type saturable absorber has been demonstrated by filling the single mode photonic crystal fiber (SMPCF) with tungsten disulfide (WS2) nanosheets. The modulation depth, saturable intensity, and non-saturable loss of this SA are measured to be 3.53%, 159 MW/cm2 and 23.2%, respectively. Based on this SA, a passively mode-locked EDF laser has been achieved with pulse duration of 808 fs and repetition rate of 19.57 MHz, and signal-noise-ratio (SNR) of 60.5 dB. Our results demonstrate that the cell-type WS2 nanosheets SA can serve as a good candidate for short-pulse mode locker.

Stable Similariton Generation in an All-Fiber Hybrid Mode-Locked Ring Laser for Frequency Metrology

“…Compared with the active ML technique [7]- [9], the passive ML technique has the advantages of flexibility and compactness [10]. Previous studies on passive ML were focused on a nonlinear polarization evolution (NPE) [11] and a semiconductor saturable absorber mirror (SESAM) [12] because their fast amplitude modulation can yield USP quality.…”

“…Previous studies on passive ML were focused on a nonlinear polarization evolution (NPE) [11] and a semiconductor saturable absorber mirror (SESAM) [12] because their fast amplitude modulation can yield USP quality. However, the NPE mechanism and SESAMs have some disadvantages, including environmental sensitivity and complicated packaging and fabrication [10]. An alternative approach based on carbon V. Lazarev nanotubes (CNTs) has been widely used in passively ML fiber lasers as saturable absorber (SA) because of its unique properties, such as ultrafast recovery time and ease of integration into a fiber cavity [13]- [15].…”

“…Recently, graphene was used for the passive ML of lasers [16], [17]. However, graphene has two main disadvantages: weak modulation depth and the difficulty of creating an optical bandgap [10]. Hence, most research has focused on the study of other nanomaterials [18]- [20].…”

Fiber-integrated tungsten disulfide saturable absorber (mirror) for pulsed fiber lasers

“…The PCFbased SAs can supply strong interaction effect and large nonlinear effect, but their fabrication processes are complicated according to the previous report. 108 The microfiber-based SAs are attractive for long light-matter interaction length, making such SAs as light modulator and high nonlinear device simultaneously. As in Ref.…”

“…[60][61] In the laser cavity, these SAs are usually pasted on fiber ferrules, or embedded in the air channels of photonic crystal fiber (PCF), 30,36,67,77,108,[119][120][121][122][123][124] or deposited on microfiber or side polished fiber (SPF). 56,58,59 The fiber ferrule-type SAs have inherently short nonlinear interaction length.…”