采用闪耀光栅作为色散元件,构建了前向、后向输出两种结构的可调谐掺Yb3+光子晶体光纤激光器,并对其输出特性进行了分析研究。在抽运功率5.75W时,前向输出结构实现了1050.6～1110.2 nm的连续调谐输出,光谱线宽约0.1 nm,边模抑制比大于44 dB。在调谐激光波长为1085 nm时,得到最高输出功率677 mW。结构改进的后向输出结构的可调谐输出结构在抽运功率4.43 W,调谐波长1075 nm,实现了2.21 W的功率输出,斜率效率为73％;调谐范围50.9 nm(1042.1～1093 nm),光谱线宽小于0.08 nm,边模抑制比大于50 dB。两种结构的可调谐激光器输出均为线偏振光,偏振度大于89.5％。

A forward output and a backward output tunable Yb-doped photonic crystal fiber laser (PCFL) with a blazing grating as a tuning element are demonstrated. For the forward output tunable PCFL, when the absorbed pump power is 5.75 W, a tuning range of 59.6 nm from 1050.6～1110.2 nm is obtained. The 3 dB bandwidth is around 0.1 nm. Side-mode extinction is more than 44 dB. A maximum output power of 677 mW is obtained with a slope efficiency of 14% for a tuning wavelength of 1085 nm. Over the whole tuning range, the variety of output power is less than ±0.34 dB. For the backward output configuration, it is tunable over 50.9 nm when the absorbed pump power is 4.43 W. For all tuning wavelengths, the 3 dB bandwidth is less than 0.08 nm, side-mode extinction is better than 50 dB. When the tuning wavelength is 1075 nm, a maximum output power of 2.21 W is obtained with a slope efficiency of 73%. For the two configurations tunable PCFL, output of both two lasers are linearly polarized and the polarization extinction ratio is more than 89.5％. The effect of re-absorption in ytterbium doped active fiber on the tuning range is also discussed.