定义：通过自动调整功率衰减程度来减小光束强度噪声的装置。

激光功率稳定系统是用来减小激光光束中的强度噪声的装置。工作原理：电场控制的衰减器可以控制光功率，而受控制的信号是要测量的入射功率（前向反馈）或者输入功率（反馈）。当测量的功率太高时，衰减会相应提高，反之亦然。这样可以稳定激光器功率，也就是降低强度噪声。 
最常用的方法是采用电学反馈回路，例如PID类型。电光调制器可用来控制功率，且伺服系统带宽很高。合理设计反馈电路对于实现在大带宽范围内有效抑制噪声非常重要。

Definition: devices for reducing the intensity noise of an optical beam by automatically adjusting the degree of power attenuation

A noise eater is a device made for reducing the intensity noise in a laser beam. The principle of operation is that the optical power is reduced with an electrically controllable attenuator, and the control signal is derived from the input power (feedforward scheme) or the output power (feedback scheme) as measured with, e.g., a fast photodiode. Essentially, the attenuation is increased when the power is measured to be too high, and vice versa. This makes it possible to stabilize the laser power, i.e., to decrease intensity noise.

The most common approach is that based on an electronic feedback loop, e.g. of a PID type. An electro-optic modulator can be used to control the power throughput with a high servo bandwidth. Proper design of the feedback electronics is vital for achieving effective noise suppression over a large bandwidth. Alternatively, it is possible to use a feedforward method.

An alternative method is to directly influence the laser output power with some technique of laser stabilization. However, a noise eater can be a good solution if the laser is not suitable for such an intervention.