光子晶体光纤中超连续谱产生的理论与实验研究

研究了光子晶体光纤中超连续激光光源的产生机理.利用非线性偏振旋转技术产生的中心波长为1 556.0 nm的飞秒光脉冲作为泵浦光源,在69 m长的高非线性光子晶体光纤中,得到了20 dB带宽约为140 nm的超连续谱；采用实验和数值模拟方法,研究了不同泵浦功率下超连续谱形成的过程.结果表明,在不同的泵浦功率下,超连续谱的形成机理不同,在各种非线性效应的共同作用下,泵浦光脉冲的峰值功率越高,得到超连续谱的带宽越宽,实验与数值模拟结果一致.另外,要想获得平坦的宽带超连续谱,必须选择合适的光纤长度.

Experimental and Numerical Study of Supercontinuum Generation in Photonic Crystal Fiber

Formating mechanism of supercontinuum generation in highly nonlinear photonic crystal fiber is studied.Using nonlinear polarization rotation technique,a stable femtosecond optical pulse with the central wavelength of 1 556.0 nm as pumping source is obtained,and by delivering this pulse into a highly nonlinear photonic crystal fiber,a supercontinuum with the 20 dB bandwith about the 140 nm has been obtained in experiment; Supercontinuum generation in different pump power was experimentally and numerically investigated.It is shown that supercontinuum has the different formatting mechanism with different pump power,and under various nonlinear effects,the more higher of the pump power; the more wide of the supercontinuum.It is found that qualitative agreement between the experiments and the simulations,the simulations shows that it exists an optimal fiber length for generation of the flat,broad supercontinuum.The SC band bandwidth will became smoother and broader by the frequency chirp.