Particular embodiments of the present invention relate generally to
semiconductor lasers and laser scanning systems and, more particularly,
to schemes for controlling semiconductor lasers. According to one
embodiment of the present invention, a laser is configured for optical
emission of encoded data. At least one parameter of the optical emission
is a function of a drive current I.sub.GAIN injected into the gain
section of the semiconductor laser and one or more additional drive
currents I/V.sub.PHASE, I/V.sub.DBR. Mode selection in the semiconductor
laser is altered by perturbing at least one of the additional drive
currents I/V.sub.PHASE, I/V.sub.DBR with a perturbation signal
I/V.sub.PTRB to alter mode selection in the semiconductor laser such that
a plurality of different emission modes are selected in the semiconductor
laser over a target emission period. In this manner, patterned variations
in the wavelength or intensity profile of the laser can be disrupted to
disguise patterned flaws that would otherwise be readily noticeable in
the output of the laser.