Numerical Analysis of the Modulation Dynamics in an Integrated Three-Section MOPA Using a Voltage Driven Traveling-Wave Model

We numerically investigate the modulation dynamics in an integrated three-section MOPA using a voltage driven traveling-wave model. The three-section device includes a distributed feedback laser, a modulation section, and a high power tapered amplifier. Both small and large modulation signals are considered, as well as binary data with pseudorandom sequences. The results indicate that dynamic responses of the modulation and amplification sections produce counteracting effects, giving rise in some cases to a reduced chirp, a faster step response, and a decrease of the patterning effects in comparison with the behavior of a single amplifier. In addition to the speed of the carrier response, two dynamical effects are relevant: the reverse current dynamics in the modulation section and the gain saturation dynamics in the amplifier section.