Measurements of small-signal intensity modulation from direct-modulated distributed feedback (DFB) semiconductor lasers after propagation in dispersive fiber have previously been used to extract intrinsic laser chirp parameters such as linewidth enhancement factor and crossover frequency. Here, we demonstrate that the simple rate equations do not satisfactorily account for the frequency response of real DFB lasers and describe some experimental techniques that conveniently determine the precise laser chirp. Implications for simulation of high-speed lightwave systems are also considered.
Eva Peral, William K. Marshall, Amnon Yariv, Life Fellow, and Fellow OSA, "Precise Measurement of Semiconductor Laser Chirp Using Effect of Propagation in Dispersive Fiber and Application to Simulation of Transmission Through Fiber Gratings," J. Lightwave Technol. 16, 1874- (1998)