以248 nm的KeF准分子激光器为光源,基于相位掩模法,研究了大模场面积双包层光纤(LMA-DCF)光栅的刻写技术。在20/400 μm的LMA-DCF中制备出中心波长1076.11 nm,基模反射率大于99.9%,3 dB带宽0.32 nm的光纤布拉格光栅(FBG)。用已制备的FBG作为腔镜,采用分立的光学元件后向抽运掺Yb³⁺光纤激光器,实现了144 W的稳定激光输出,斜率效率为60%,输出激光光谱特性同FBG的光谱特性一致。

Using a 248 nm KeF excimer laser as the UV light source,the inscription method of fiber Bragg grating (FBG) on large-mode-area double-clad fiber (LMA-DCF) was studied with phase mask technique.The center wavelength of the fabricated FBG was at 1076.11 nm with a 3 dB bandwidth of 0.32 nm and reflectivity of 99.9% in the fundamental mode.The FBG was then applied to a Yb³⁺-doped double-clad fiber laser as a highly reflective cavity mirror.The 144 W of stable output power with a slope efficiency of 60% was achieved.The spectral characteristics of the output laser matched well with that of the FBG and an excellent Gaussian beam shape was achieved.