Parametric oscillatory instability in Fabry-Perot interferometer

We present an approximate analysis of a nonlinear effect of parametric osci llatory instability in Fabry-Perot (FP) interferometer. The basis for this effect is the excitation of the additional (Stokes) optical mode with frequ ency omega (1) and of the mirror's elastic mode with frequency omega (m), w hen the optical energy stored in the FP resonator main mode with frequency omega (0) exceeds the certain threshold and the frequencies are related as omega (0) similar or equal to, omega (1) + omega (m). This effect is undesi rable in laser gravitational wave antennae because it may create a specific upper limit for the value of energy stored in FP resonator. In order to av oid it the detailed analysis of the mirror's elastic modes and FP resonator optical modes structure is necessary. (C) 2001 Published by Elsevier Scien ce B.V.