以重复频率为250 MHz、脉冲宽度为140 fs的锁模掺镱光纤激光器作为泵浦源, 用拉锥光子晶体光纤产生超连续光谱.优化光纤拉锥直径后, 在泵浦光脉冲能量达到0.36 nJ时, 产生的超连续光在－20 dB水平的光谱覆盖范围为470～1 620 nm；继续增加泵浦光脉冲能量, 光谱范围在可见光区已无显著增大.超连续光谱产生的数值模拟结果与实验符合良好, 且模拟中超连续光谱产生的部位为光纤靠近入射端的过渡段, 与实验中观察到的现象吻合.以25 GHz高重复频率脉冲激光作为泵浦源, 保持0.36 nJ脉冲能量, 用优化后的光纤进行超连续光谱产生, 得到光谱在－20 dB水平上覆盖可见光区的范围为450~700 nm, 超过12 h的光谱演化测试表明了超连续光的长期稳定性.

By using an ytterbium fiber laser with a repetition rate of 250 MHz and a pulse duration of 140 fs as the pump source, the expreiments of broadband supercontinuum generation were conducted with tapered Photonic Cystal Fibers (PCFs). After optimizing the waist diameter of the PCF tapers, when the pulse energy of the pump source is up to 0.36 nJ, a broadband spectrum was generated in the range from 470 nm to 1 620 nm at the level of －20 dB. After reaching up to 0.36 nJ, further increasing the pulse energy of the pump does not strongly benefit the spectral bandwidth in the visible range. The supercontinuum generation is verified by the simulation. In the simulation, the supercontinuum is generated in the input transition section, which is also observed in the experiments. By keeping the pulse energy of 0.36 nJ, this fiber survives with the high repetition rate pulses of 25 GHz, and obtains the －20 dB level spectral range from 450 nm to 700 nm in the visible range. A more than 12 h spectral evolution measurement shows the stability of the generated supercontinuum.