A 1150-W 1018-nm Fiber Laser Bidirectional Pumped by Wavelength-Stabilized Laser Diodes

This paper presented a high-power 1018-nm ytterbium-doped fiber laser pumped by wavelength-stabilized laser diodes in bidirectional pumping structure. A record output power reaching 1150 W was achieved, along with a slope efficiency of 82.9% and a beam quality factor of M² = 1.96. The output spectrum exhibited an efficient amplified spontaneous emission and parasitic lasing light suppression. The thermal effects were studied to verify the reliability of our 1018-nm FL as a practical 1-kW light source. Besides, an important investigation was made on the 1080-nm fiber laser tandem pumped by 1018-nm fiber lasers, the experimental result of which was reported to be 3712 W.

I. Introduction

Nowadays high power fiber lasers (FLs) with their outstanding advantages have been widely used in many industrial, military and scientific applications [1]– [3]. For a FL, the pumping configuration is of critical importance, which can be divided into two major categories: direct-pumping configuration [4], [5] and tandem-pumping configuration [6] , [7]. As far as we know, the highest power of single output fiber was reported by IPG in 2009 based on the tandem-pumping, taking advantage of the relatively short wavelength (1000–1030 nm) FLs employed as the pump source in tandem-pumping to reduce the quantum defect in the active fiber, which leads to less thermal load and larger pumping capacity [8]. Hence, the tandem-pumped FLs have the potential to raise the output power limit [9] . Consequently, rising attention has been paid by researchers worldwide to achieve higher output power of these short wavelength FLs, especially 1018 nm ytterbium-doped fiber laser (YDFLs) [10]–[14].