Semi-transparent monitor detector for surface emitting light emitting devices

摘要

A structure for providing direct feedback of power emitted by a surface emitting light emitting device and the subsequent optical power control of the device is disclosed. In a preferred embodiment, an array of vertical cavity surface emitting lasers emit light having a wavelength which is partially detected by an array of photodetectors. The semi-transparent photodetectors array has an absorption coefficient which is relatively small at the wavelength of light emitted by the lasers. Most of the emitted light will be transmitted through the detectors while a small insignificant fraction in magnitude is absorbed and converted to photocurrent for monitoring the output power of the devices. The structure of the device of the present disclosure is simple, readily fabricated through uncomplicated techniques and of materials which do not effect the beam characteristics of the surface emitting devices.