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

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.<
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