We roundly investigate the chaos and hyperchaos of drefl from different aspect embodying the character of chaos and find that drefl can be in chaotic or hyperchaotic state at some conditions . it is firstly founded that the drefl has two attracting basin at some conditions 从表现混沌的不同侧面对双环掺铒光纤激光器的混沌和超混沌进行了全面研究，在一定的参数条件下，双环掺铒光纤激光器存在混沌和超混沌状态。
In the method of impulsive synchronization , both seriate system and discrete system have been discussed . a series of discrete hyperchaos systems that have the lowest dimension have been constructed , and we have achieved the impulsive synchronization of discrete system in circuit 脉冲同步法中，分别从连续系统和离散系统两方面进行讨论，构造出一系列具有最低维数的离散超混沌系统，并通过电子线路实现了离散系统的脉冲同步。
