Volterra functional series expansions for semiconductor lasers under modulation

Abstract

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 /spl epsiv/. Second-harmonic distortion (2HD) shows two maxima at half relaxation oscillation frequency /spl Omega//sub R//2 and at /spl Omega//sub 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 /spl Gamma//sub R/ reveal their precise dependence on /spl epsiv/ and differential gain A. For step input, the turn-on delay t/sub on/ and the overshoot P/sub P//P/sub on/ expressions of our model are only functions of /spl Gamma//sub R/ and /spl Omega//sub R/. P/sub P//P/sub on/, and the ringing phenomena decrease with increasing bias current level. >