Assessment of laser intensity noise spectrum from rigorous numerical simulation of singlemode laser rate equations

A rigorous numerical method of solving the stochastic laser rate equations is investigated. Using this method, statistically correct numerical simulations of the relative intensity noise (RIN) spectrum at laser output are performed. The method is validated by comparison of the simulation results with analytical theoretical predictions. To estimate the RIN spectrum the periodogram technique is used. The impact of the number of periodograms, number of points, and time interval width on the RIN spectrum estimation is discussed. It is shown also that the usual methods of solving deterministic nonlinear differential equations should not be used to obtain by simulation the RIN at the laser output.