A method and apparatus for monitoring the optical power output of a VCSEL
uses refracted ray coupling to direct rays refracted out of an optical
transmission medium, towards a photodetector. The photodetector is coupled
to feedback circuitry and laser control circuitry capable of adjusting the
VCSEL based on the monitored power output. A portion of the rays that
enter the optical fiber are refracted out of the optical fiber by means of
high-index materials and directed toward the photodetector by reflective
surfaces situated around the coupling region in which the VCSEL is coupled
to the optical fiber.
