Tapered large-core 976 nm Yb-doped fiber laser with 10 W output power

Abstract

We report on a tapered large-core Yb fiber laser operating at 976 nm emission wavelength. It was realized using a high-numerical aperture large-core fiber with 126 µm core diameter, which was fabricated by powder-sinter technology and shows a very homogeneous step-index profile. The end of the fiber is tapered down to match a single-mode fiber containing a fiber Bragg grating. Using the benefits of core-pumping and the feedback of the spliced fiber Bragg grating, we achieved efficient pump light absorption and wavelength stable 976 nm lasing with single-mode performance. We could demonstrate 10 W laser power out of a 10 µm fiber core with a slope efficiency of 31% with respect to the launched pump power. The presented device is well-suited for fiber-coupled pumping of amplifiers for high peak power.

Detailed numerical investigation of the interaction of longitudinal acoustic waves with fiber Bragg gratings in suspended-core fibers

“…The reduced diameter horn tip to match with SCF cores of diameter larger than 5 mm can be implemented by tapering silica rods (e.g. tapered diameter from 1 mm to 5 um) using commercial Vytran machines and a technique proposed in [17]. Horn tips for SCFs of core diameters smaller than 5 mm can be made by splicing a tapered horn (e.g.…”

Yb^3+-doped double-clad phosphate fiber for 976 nm single-frequency laser amplifiers

“…In order to overcome this problem, various techniques have been utilized to suppress the competitive laser at long wavelengths. So far, ring-doped fiber [30], jacked air-clad fiber [31,32], rod-type photonic crystal fiber [9,10], tapered fiber [33], depressed-clad hollow fiber [34], and spectral gain discrimination [35] have been demonstrated to achieve high power output around 980 nm. These special waveguide designs successfully realized in silica fibers should be able to be applied to phosphate fibers.…”

46.9 W 980 nm diffraction-limited monolithic fiber laser based on 20/80 Yb-doped fiber

“…However, the increase in core area/diameter usually leads to an increase in high-order modes supported by the fiber; thus, the beam quality deteriorates as shown in [8]. Interestingly, some novel double-cladding YDF designs, such as W-profile fiber [4], tapered large-core fiber [10], saddletype fibers [11], etc., have been demonstrated to realize 10 W all-fiber single mode fiber lasers. Currently, the bestperforming 980 nm laser is achieved using Yb-doped photonic bandgap fiber with an output power of 151 W, a slope efficiency of 63%, and an M 2 factor of 1.25 [12].…”