An integrated semiconductor device comprising a laser on a substrate, the laser
having an active layer and a current-induced grating, such as a current-injection
complex-coupled grating, within a laser cavity producing a single-mode output light
signal at high data rates (622 Mb/sec) in isolator-free operation. The grating
has a coupling strength product L greater than 3, where is the coupling
coefficient and L is the length of the laser cavity. In certain embodiments, the
laser is a distributed feedback (DFB) laser that emits light at a wavelength of
about 1.5 m. The strong current-induced grating prevents mode hopping between
multiple degenerate Bragg modes. The laser is also characterized by excellent immunity
from optical feedback, and can be operated without an isolator at high data rates.
