系统地研究了在非线性掺镱光纤放大器中产生宽带光谱的特性,对不同种子脉冲激光的中心波长、放大器增益光纤长度对光谱输出特性的影响进行系统实验及分析。实验中采用非线性偏振旋转锁模技术获得非线性放大器的种子光,输出为耗散孤子脉冲。当种子脉冲激光中心波长为1041 nm、放大器的增益光纤长度为8 m时,获得了较好的平坦宽光谱,波长范围为1040~1600 nm时,其平坦度约为10 dB,其中1040~1250 nm波长范围的宽光谱平坦度小于1.5 dB。

The influences of central wavelength of the seed pulse and gain fiber length of the amplifier on the characteristics of broadband spectra are systematically investigated based on nonlinear ytterbium-doped fiber amplifiers. The dissipative solitons from the nonlinear amplifier are obtained by using the nonlinear polarization rotation mode-locking technique. The best flat wide spectrum with wavelength range of 1040-1600 nm is obtained when the center wavelength of the seed pulse is 1041 nm and the gain fiber length of the amplifier is 8 m. The flatness is about 10 dB, and the wide spectral flatness is less than 1.5 dB from 1040 to 1250 nm.