双稳激光器的不稳定性本质研究

本文从非线性方程稳定性理论出发,给出了双稳激光器速率方程的稳定性三条件,指出了其中两个条件分别是产生双稳和自脉动的不稳定性条件,证明了双稳与光功率曲线出现负斜率的区域相对应,这时小信号分析方程有单调上升解,自脉动则与无稳定解的区域相对应,这时小信号分析方程有振荡上升解。另外两者都属于“三次”非线性现象,但是要在g达到一定的非线性时才可能产生自脉动。 关键词：

STUDY OF THE INSTABILITY OF BISTABLE INJECTION LASERS

The theory of instability for non-linear differential equations is applied to the rate equations of a bistable laser. It is found that there are three conditions have to be fulfilled in order to make the system stable. The first condition is automatically fulfilled for ordinary bistable lasers. The second and third conditions are related to self-pulsation and bistable characteristics of the laser respectively. It has been shown that if the third condition is not fulfilled in certain region, the linearized rate equation for small-signal will have a monotonously increasing solution in that region. This means that the light power output curve has a negative slope region, which would result in bistable character. On the other hand, if the second condition is not fulfilled, the linearized rate equation for small-signal will have enhanced oscillating solutions. This means that the laser will self-oscillate as long as the third condition is fulfilled in that region. Besides, it is also shown that both the self-pulsation and the bistable behaviours of the laser are closely related to the non-linearity of g(N) function, which is the necessary condition for having a linearized rate equation of third order.