Parametric oscillatory instability in Fabry-Perot interferometer

We present an approximate analysis of a nonlinear effect of parametric oscillatory instability in Fabry-Perot (FP) interferometer. The basis for this effect is the excitation of the additional (Stokes) optical mode with frequency omega (1) and of the mirror's elastic mode with frequency omega (m), when 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 undesirable 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 avoid it the detailed analysis of the mirror's elastic modes and FP resonator optical modes structure is necessary. (C) 2001 Published by Elsevier Science B.V.