In general, a complex-coupled distributed feedback (DFB) semiconductor laser includes a grating formed by grooves through at least a part of an active region of a laser cavity. The complex-coupled DFB laser may be configured with a wavelength monitoring section and may be configured to provide facet power asymmetry. The wavelength monitoring section may include a second-order grating section configured to emit radiation (e.g., vertical radiation) from a side of the DFB laser for monitoring.