  Cavity optomechanics is a suitable field to explore quantum effects on
macroscopic objects and develop quantum technology applications. A perfect
control of the laser noise is required to operate the system in such extreme
conditions necessary to reach the quantum regime. In this paper, we consider a
Fabry-Per\'ot cavity, driven by two laser fields, with two partially reflective
SiN membranes inside it. We describe the effects of amplitude and phase noise
on the laser introducing two additional noise terms in the Langevin equations
of the system's dynamics. Experimentally, we add an artificial source of noise
on the laser. We calibrate the intensity of the noise, inject it into the
system, and check the validity of the theoretical model. This procedure
provides an accurate description of the effects of a noisy laser in the
optomechanical setup and allows for quantifying the amount of noise.
