In this paper a definition of static stability is given and the output power stability of optical bistable devices in the condition of steady operation is discussed. It is pointed out that the multi-beam interference device is better than the two-beam one in static stability and the nonlinear, especially the exponential feedback system is better than the linear one. A laser power stabilizer has been fabricated for the first time by authors using a polarization interference OBD with exponential feedback and a high static stability near 50 haa been obtained. The experimental results are consistent with, the calculated values.