半导体激光器混沌法拉第效应控制方法

Control of chaos in a semiconductor laser using the Faraday effect

提出了外腔延时反馈半导体激光器法拉第效应控制下的新激光系统,构造出两种类型结构光路,建立了法拉第效应控制下的延时负反馈、延时正反馈激光动力学物理模型,研究了激光混沌控制与反控制等.利用法拉第效应原理及磁致旋光性和系统特点,调节控制光路中的光旋转角度和光延时间可实现双参数控制激光器,控制激光到双周期、三周期及多周期,使激光产生拍动等现象,反控制激光周期到混沌等.发现了以磁致旋光角分布的激光混沌控制与反控制区域.并研究了激光混沌控制与周期控制的动态情况,演示讨论了激光态的转化演变过程等.

We present a novel laser system with an external cavity delay feedback semiconductor laser under the control of Faraday effect. To study the chaos-control and chaos-anti-control of the laser system, we construct two types of optical path structures as two control systems of the negative feedback and the ring cavity by using the combination of the Faraday effect controller, the polarizer and the mirror. We give a physical model of laser dynamics with the delayed negative feedback or the delayed positive feedback under the control of Faraday effect. Using the Faraday effect principle of magnetic rotation and the characteristics of the system, we can achieve the double parameter control of the laser.We can shift the optical rotation angle by operating Faraday effect controller and modulate the optical delay time by performing the mirror to vary the double parameter. The laser can be controlled to a double-cycle, a tri-cycle, a multi-cycle, and beat phenomenon by using the control system of the negative feedback, etc. The periodic laser can be anti-controlled to chaos by using the control system of the ring cavity. Some control and anti-control areas formed with the distribution of magnetic rotation angular are found in the laser. For the negative feedback system under the some control cases, the chaotic laser can be controlled to some tri-cycle states between π/14 and π/9. By shifting the control parameters, the chaotic laser can be controlled to some cycle-7 states between 10π/133 and 10π/108 and another tri-cycle region is found from 10π/96 to π/8. Under other control parameters, the chaotic laser can be controlled to some cycle-8 or cycle-9 states. For the ring cavity system under the some control cases, the dual-cycle region is betweenπ/10 and π/30, the cycle-6 region is between π/4 and π/5, the cycle-13 region is found to be from π/6 to 10π/76. In another control case, the large chaos-anti-control region is found to exist between 0 and π/12. Dynamic controls of the chaotic laser and the periodic laser are also studied while the transformation and evolution of laser states are discussed.It is found that it takes about 10 ns for one state to change into another state when the control operation is applied to the laser. The control method is very useful for studying chaos-control, new laser system and its application.