基于色散傅里叶变换的孤子脉冲建立与放大研究

Research on buildup and amplification of soliton pulse using dispersive Fourier transform technique

基于色散傅里叶变换技术研究了反常色散腔内传统孤子和正常色散腔内耗散孤子建立时的孤子动力学过程。为探究脉冲在光放大器中如何随放大功率演变,实验和模拟研究了这两类孤子经放大器放大后的动态变化。结果表明,这两类孤子的光谱在建立时会经历不同的振荡过程,传统孤子光谱会由能量有剧烈振荡的调制拍频状态过渡至稳定,耗散孤子光谱则会由无序调制状态平稳展宽至稳定。在放大器中,随着放大器泵浦功率的上升,传统孤子光谱中心能量将被转移而展宽,耗散孤子光谱则在保持谱宽不变的情况下在边沿出现尖峰。这些锁模光纤激光器和光放大器中的动态孤子非线性现象在超快激光及其放大系统中有着潜在的应用价值。

The buildup dynamics of conventional solitons with net anomalous dispersion and dissipative solitons with normal dispersion were studied using dispersive Fourier transform technique.In order to explore how these pulses evolve with the amplification power in the optical amplifier,experiment and simulation were carried out to investigate dynamic changes of the two kinds of solitons after amplification by amplifier.The results show that spectra of the two kinds of solitons undergo different oscillations during the establishment,the spectra of conventional solitons start from a modulated beat state with violent energy oscillation then transit to a stable state,while the spectra of dissipative solitons expand steadily from a disordered modulated state to a stable state.As the pump power of the amplifier increases,for conventional soliton,the center energy of spectrum will be transferred and the spectrum will be broadened,while the spectrum of dissipative soliton will exhibit a sharp peak at the edge with unchanged spectral width.These dynamic nonlinear phenomena in mode-locked fiber lasers and optical amplifiers have potential application value in ultrafast lasers and the corresponding amplification systems.