Transient chirping in distributed-feedback (DFB) lasers: effect of spatial hole-burning along the laser axis

Abstract

An analysis of the chirping behavior of directly modulated distributed-feedback (DFB) lasers which takes into consideration the effects of spatial hole-burning along the laser axis is discussed. Rate equations including these effects are derived. To calculate the rate equations, the threshold condition of phase-shifted DFB lasers with a nonuniform refractive index distribution is analyzed. The calculations are carried out on phase-shifted DFB structures under the condition of random nonreturn to zero modulation at 1.8 Gb/s. The results show that the spatial hole-burning along the axis significantly affects the chirping behavior, adding to the effects induced by the spectral hole-burning alone.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>