Abstract

DBR lasers and multisection DFB lasers have recently been used in fast-wavelength-switched (FWS) experiments with noncoherent and coherent detection.^1-3 Thermal modulation of the active-layer refractive index causes the optical frequency to drift after a wavelength switch, and this may impose a limit on either the time duration of a data packet^1,2 or the acquisition time of a locking circuit in the receiver.³ Consequently, the time that a switched signal remains within the receiver bandwidth (the residency time) is an important parameter. The residency time is assessed experimentally and theoretically for FWS systems based on two-section DFB lasers, which are well suited for certain applications, and heterodyne detection. The dependence of the FM response, IF spectral broadening, and residency time on the bias condition of the laser is examined.

© 1995 Optical Society of America