When laser diodes are working at steady state, unstable or fluctuated optical power creates noise with in the system. There are different reasons for this noise. In this study, in order to make reduction in power fluctuated noise, relative intensity noise analysis (RIN) is realized with the previously developed system theory of the laser diode with non-linear optoelectronic feedback. Volterra series expansion is analyzed for this laser diode system in order to see the effect to RIN with in the system approach. RIN equalities are defined for each Kernel (Hi, HZ, H 3,...H n) from the small signal transfer functions that is obtained due to the Volterra operators. From this definition, RIN transfer function is obtained from the first Volterra Kernel due to the feedback constant (K) and feedback delay time (t o ). The remaining RIN equalities for other Volterra Kernels are given and generalized expressions are obtained for these equalities.