三芯光纤耦合器的开关和传输特性研究

Study on the propagation and switching performance of three-core nonlinear fiber coupler

利用耦合非线性薛定谔方程组(CNLSEs),研究了超短孤子脉冲在非线性三芯光纤耦合器中的传输和开关特性。分析了正常色散和反常色散对于开关特性的影响。通过调整非线性参数能够优化开关特性,降低了开关阈值功率和提高了能量转移效率。采用分步傅里叶法(SSFM)的仿真,数值模拟了在正常色散区和反常色散区的不同开关特性,以及当非线性参数从1.5增大到2.5时开关性能的变化。研究表明:在反常色散区中,耦合器具有明显的开关特性。在三芯耦合器中,当三根光纤的非线性参数同时增加时,阈值功率由Po12显著降低至Po4.12,能量转移效率由40%显著提升至65%。

Based on coupled nonlinear Schrodinger equations （CNLSEs）, the ultrashort soliton pulses propagation and switching in three-core nonlinear fiber couplers are investigated. The effects of the normal dispersion and anomalous dis- persion on switching characteristics are highlighted. It is demonstrated that the nonlinear coefficient can lower the switc- hing threshold power and increase significantly the switching efficiency, The different switching characteristics in the nor- mal dispersion and anomalous dispersion regions are numerically simulated, using the split-step Fourier method（SSFM）. Besides, the nonlinear coefficient can also improve the switching characteristics when it increases from 1.5 to 2. 5. The research shows that NLDC can get good switching characteristics in the anomalous dispersion region. It is proved that the threshold power decreases significantly from 12 to 4. 12 and the switching efficiency increases from 40 percent to 65 per- cent when the value of three cores＇ nonlinear coefficients increase at the same time.