Particular embodiments of the present invention relate generally to semiconductor lasers and laser projections systems and, more particularly, to schemes for controlling semiconductor lasers. According to one embodiment of the present invention, a laser having a gain section (16), a phase section (14) and a wavelength selective, section (12) is configured for optical emission of encoded data. The optical emission is shifted across a plurality of laser cavity modes by applying a quasi-periodic phase shifting signal I/V f to the phase section (14) of the semiconductor laser. The amplitude of the quasi-periodic signal transactions periodically between a maximum drive level (A) and a minimum drive level (B) at a frequency that varies randomly over time.