METHOD AND APPARATUS FOR REDUCING OPTICAL SIGNAL SPECKLE

摘要

An optical signal generator is configured with an associated control system and driver configured to reduce speckle. Speckle reduction occurs by pulsing the drive signal between a first current level and a second current level. These pulses force the optical signal generator to introduce oscillations into the optical signal. The coherence of the emitted light is reduced during the period of oscillations in the optical signal, which reduces speckle. In one embodiment, the pulsing of the drive signal brings the drive signal down to a level near or below threshold, which in turn intermittently turns off the optical signal output. Returning the optical signal to a desired optical output intensity introduces the speckle reducing oscillation. The pulse frequency, and duty cycle is controlled by a duty cycle control signal to modulate overall optical power and adjust amount of despeckle.