Nonlinear System Modeling of Semiconductor Lasers Based on Volterra Series

Abstract

Starting from the simple monomode rate equations of semiconductor lasers a very comprehensive nonlinear equivalent circuit diagram of analog modulated semiconductor lasers is presented. For distortion analysis this equivalent circuit diagram is investigated using Volterra series and for the first time the Volterra kernels of semiconductor lasers are derived. By means of the Volterra kernels harmonic, intermodulation and other nonlinear distortions can easily be obtained.Using Volterra series the complex amplitude of any nonlinear product is exactly calculated because all formulae are derived analytically. The results are for all cases equal to those obtained from simulation of the rate equations. Nonlinear distortions are calculated for two different input signals: harmonic modulation and stochastic modulation. The dependence of nonlinear distortion on laser parameters is investigated and the influence of reflections is estimated.

Isolator-free DFB laser for analog CATV applications

“…Czylwik's analysis [25] included the time delay of the reflected waves in the feedback term to predict the upper bound on the harmonic distortion due to reflected waves. He showed an excess 2nd, 3rd, and 4th order harmonic distortion for the laser diode under -20 dB and -30 dB back-reflection ratios for distances 1 m and 3 m. However, he did not report on the other feedback regions, nor the laser diode's different behaviors under optical back-reflect ions.…”

“…11 -4.15 on page 75 show the measured average relative intensity noise for 1300 nm DFB at 1 GHz frequency offset. The DFB laser was operated at five different bias current levels,25,30,35,40, and 60 mA. The measured unintended back-reflection th at attributed to the connectors was -45 dB.The RIN exhibits a peak at the laser's relaxation oscillation frequency, this peak shifts Relative intensity noise measurement experimental setup.…”