利用飞秒激光微加工技术, 可以在光纤纤芯内直写出布拉格光栅, 它与传统的光纤光栅制作方法相比, 具有耗时短、无需光敏光纤、周期可任意设定、光栅稳定性高等优点。采用800 nm钛宝石飞秒激光器, 在Hi1060光纤内写入一支8 mm长的布拉格光栅, 光纤光栅的周期为2.9 μm, 这是中心波长为1 042 nm的八阶光纤布拉格光栅。将所得光栅与一段有源的双包层光纤熔接, 作为激光输出镜, 利用975 nm的LD光纤模块作为泵浦源, 采用端泵浦技术构成双包层光纤激光器。双包层光纤采用Nufern公司镱(Yb3+)离子掺杂双包层光纤, 光纤长度3 m。所得激光器的输出功率为71.1 W, 中心波长1 042 nm, 带宽约为0.8 nm。

A fiber Bragg grating(FBG) was inscribed into Corning Hi1060 fiber by focused irradiation of 800 nm femtosecond laser pulses. The FBG was 8 mm long with the period of 2.9 μm, which corresponds to an eight-order grating for 1 042 nm. As the output coupling mirror, the FBG was spliced to a 3 m long double-clad fiber to form the cavity of a fiber laser. A 975 nm laser diode fiber module was used as the end-pump light source. The double-clad fiber was provided by Nufern, with the core and cladding diameters of 10 μm and 125 μm, respectively. The laser output power was 71.1 mW in our experiment, and the center wavelength was 1 042 nm, with the bandwidth of 0.8 nm.