Reduction of second- and third-order harmonic distortion bynonlinear absorption in gain-coupled distributed-feedback laser diodes

摘要

We have calculated the characteristics of second- and third-ordernharmonic distortion in gain-coupled distributed feedback (DFB) lasersnusing a set of three rate equations. In these calculations, thenrelaxation oscillation, nonlinear gain compression, and nonlinear lossncompression are taken into account. We have found that modulationndistortion due to nonlinear gain compression is reduced significantly innthe gain-coupled DFB laser of absorptive-grating type. This improvementnoccurs because gain compression is compensated by loss compressionnwithin the grating