PACKAGING OF HIGH-DENSITY FIBER LASER MODULES USING PASSIVE ALIGNMENT TECHNIQUES

A novel method for packaging a laser-fiber module is explored in which the critical laser-fiber alignment is carried out, not with the usual active means, i.e., with the laser activated, but by a passive method based on the registration principles of photolithography. The new method relies on an index scheme in which fiducial marks are lithographically placed on the laser chip and on a fiber carrier. At 850 nm, using the index technique with cleaved multimode fibers, it has been possible to achieve the same laser fiber coupling efficiency as attained by active alignment; with cleaved single-mode fibers about 80% of the active alignment coupling efficiency was achieved. Details of the new index-alignment method are discussed, and a brief description of an improved computer-controlled version of the apparatus is given.