Volterra functional series expansions for semiconductor lasers under modulation

An analytical model based on Volterra nonlinear functionals applied to semiconductor lasers has been developed. Analytical expressions are obtained for different laser diode responses, giving powerful tools for analysis. For harmonic input, the response is given including the gain compression factor ε. Second-harmonic distortion (2HD) shows two maxima at half relaxation oscillation frequency Ω_R/2 and at Ω_R, in agreement with experiments; the residual dc component due to nonlinearities is estimated and experimentally verified. Dynamic frequency deviation as function of bias current shows resonant characteristics. Relaxation frequency and damping rate Γ_R reveal their precise dependence on ε and differential gain A. For step input, the turn-on delay t_on and the overshoot P_P/P_on expressions of our model are only functions of Γ_R and Ω_R. P_P/P_on, and the ringing phenomena decrease with increasing bias current level