Intuitive classical approach of intensity noise in linear, phase-insensitive optical amplifiers

Summary form only given. Papers have evaluated the intensity noise at linear phase-insensitive optical amplifier output and identified it as amplified spontaneous emission (ASE). The contribution of input fluctuations and of the amplifier in output noise are not distinguishable, making impossible a description of squeezed-state amplification. Starting from a corpuscular approach of light and using Rice description of a coherent electromagnetic field, a new classical approach of intensity noise in amplifiers is proposed. It distinguishes the different sources of noise and evaluates their contribution in an intuitive but rigorous way. It also brings to the fore the effects of loss, intrinsic to the amplifier, in the intensity noise generation process. After reminding the corpuscular formalism of intensity noise and Rice representation of noise, the intensity noise at the output of linear, phase-insensitive optical amplifiers is deduced, followed by a reevaluation of the noise figure.