Low quantum noise tranquilizer for Fabry-Perot interferometer

We discuss the possibility to introduce low noise damping produced by light into mechanical oscillator (one of the Fabry-Perot (FP) resonator mirrors is the mechanical resonator). Pumping FP resonator, by light detuned from resonance one can create the positive or negative rigidity in mechanical oscillator. Such a rigidity being introduced with delay (of the order of relaxation time of FP resonator) is equivalent to additional low noise damping. We propose to introduce this damping to tranquilize (to depress) parametric oscillatory instability in FP interferometer (Phys. Lett. A 287 (2001) 331) which is undesirable in laser gravitational wave antennae.