High efficiency all-fiber cylindrical vector beam laser using a long-period fiber grating

Abstract

We demonstrate a novel all-fiber laser generating cylindrical vector beams with high slope efficiency and low threshold by introducing a long-period fiber grating into the laser cavity. Highly efficient mode conversion is realized by an LPFG at ∼1548 nm. Mode selection and spectrum filtering are achieved in combination with a two-mode fiber Bragg grating (TM-FBG). The fiber laser operates at a single wavelength of 1547.95 nm with a 30 dB linewidth of less than 0.18 nm and a side-mode suppression ratio (SMSR) of more than 56 dB. The lasing threshold and slope efficiency of the laser are 24.5 mW and 35.41%, respectively. The output power is 72 mW with an absorbed pump power of 225 mW. The variation of slope efficiency with respect to the reflectivity of the TM-FBG is investigated. Through adjusting the intra-cavity polarization controller, high-purity radially and azimuthally polarized beams are both obtained.

A High‐Efficiency All‐Fiber Laser Operated in High‐Order Mode using Ring‐Core Yb‐Doped Fiber

“…Chen et al. demonstrated a fiber laser generating cylindrical vector beam efficiently in 1.5 µm band using long period grating . In a previous work of our group, Zhang et al.…”

All-Fiber Laser With Agile Mode-Switching Capability Through Intra-Cavity Conversion

“…Fiber lasers with pure high-order-mode (HOM) output have been intensively studied in recent years owing to their unique polarization, amplitude and phase characteristics. Generally, there are several commonly used approaches to realize HOM operation, including adopting spatial light modulators [1], [2], employing long period gratings [3], [4], introducing adaptive control [5]- [7], using few-mode fiber Bragg gratings (FBGs) [8]- [10] and taking advantage of mode selective couplers [11], [12]. Currently, exploration on HOM fiber lasers has focused on power scaling [13], nonlinear conversion [4], [14], vector beam generation [15], etc.…”

Formation and Evolution of Soliton in Two-Mode Fiber Laser

“…After that, Xiao et al reported on soliton molecules in multimode fiber lasers by adjusting the waveplates inside the cavity, and observed transition states of different operations in different pump powers [33]. As a typical few-mode fiber, two-mode fiber (TMF) can support the propagation of LP 01 and LP 11 modes, and mode-selective couplers, few-mode fiber gratings, as well as lateral offset-spliced fibers have been broadly used to generate cylindrical vector beams [34]- [36] and vortex beams [37]- [39]. Dong et al reported the transverse modes switchable mode-locked fiber laser by using a two-mode fiber Bragg grating for transverse-mode selection [40].…”