含负折射介质的反向定向耦合器的时空不稳定性研究  

Spatiotemporal Instabilities in Nonlinear Asymmetric Oppositely Directional Coupler with a Negative-Index Metamaterial Channel

作　　者：易鹏[1] 项元江[1] 戴小玉[2] 丁明耀[1] 文双春[1] 

机构地区：[1]湖南大学信息科学与工程学院微纳光电器件及应用教育部重点实验室,湖南长沙410082 [2]湖南大学电气与信息工程学院,湖南长沙410082

出　　处：《光学学报》2012年第4期199-205,共7页Acta Optica Sinica

基　　金：国家自然科学基金(11004053)资助课题

摘　　要：研究含负折射介质的不对称反向定向耦合器中的时空调制不稳定性(MI),探讨了输入功率、前向波和后向波功率比和通道间的耦合系数等对时空MI的影响。结果表明:在这种新型耦合器中只有当横向波数超过一定阈值时才会产生MI,增加输入功率或减少前向波和后向波的功率比都会扩大MI增益谱的范围并最终使MI区域重合,而降低耦合器通道间的耦合系数可减少MI的增益峰值但拓宽增益谱的范围。负折射介质的电磁参数可调谐特性为实现MI的主动调控和孤子的形成提供了新的方法和手段。Spatiotemporal modulation instabilities（MI） in nonlinear asymmetric oppositely directional coupler with negative-index metamaterial are investigated.The influences of input power,power ratio of the forward-and backward-propagating waves,and coupling coefficients on the spatiotemporal MI are discussed.It is found that the MI can occur only if the transverse wave numbers satisfy the threshold condition.The results also show that increasing the input power or decreasing power ratio of the forward-and backward-propagating waves promotes the spatiotemporal MI and merges different instability regions together.Moreover,decreasing the coupling coefficient can suppress the peak gain and spread the gain spectrum.The controllable electromagnetic parameters of negative-index metamaterials will provide more methods to engineer the MI and soliton formation in this coupler.

关 键 词：非线性光学 时空调制不稳定性 反向定向耦合器 负折射介质 孤子 

分 类 号：O436[机械工程—光学工程]