METHOD AND APPARATUS FOR BACK FACET MONITORING OF MULTIPLE SEMICONDUCTOR LASER DIODES

摘要

The present invention is a novel multiple laser diode structure and method for using such structures to optically isolate the light from the different diodes. The novel structure comprises a submount on which the individual lasing elements are mounted and a back facet monitoring plate coupled to the submount. The back facet monitoring plate comprises a plurality of optically sensitive detectors that monitor the amount of laser light emanating from the back facet. Ideally, one detector should be mounted opposite a back facet for each lasing element. The submount is designed with an isolation bar that optically separates the light from individual lasing elements. The radiation thus detected by each detector emanates from the back facet of a single lasing element. The amount of back facet radiation captured by the detector is proportional to the amount of radiation emanating from the front facet of the lasing element. This information enables the system to individually monitor and subsequently control the spot power of the lasing element in a continuous closed loop fashion.