SG-DBR tunable laser linewidth and its impact on advanced modulation format transmission

In this paper, the authors characterize the linewidth of a four-section SG-DBR laser, using the self-heterodyne method, as a function of both phase current, and back and front mirror currents. The tuning curves of linewidth versus different front and back grating currents are shown. The current of the front grating is scanned from 0 to 40 mA with 0.5 mA step, while the current of the back grating is scanned from 0 to 60mA with 1mA step.