Assembly of laser-fiber arrays

This paper describes techniques and machinery for first-level packaging of laser-to-fiber interconnects using batch assembly and active alignment. These techniques are economical because the costs of labor-intensive processes, such as parts handling, fiber-polishing, and alignment, are shared among the many elements of the array. Using these techniques, prototype packages have been built consisting of 32-wide arrays of 1300 nm lasers coupled to 32-wide arrays of single-mode fiber-optic stubs. Building the package involves three steps: (1) preparing the laser array for handling and alignment by soldering it to a metallized silicon carrier; (2) building the fiber array by stripping the fibers, placing them precisely into etched silicon V-grooves, bonding them in place, and polishing both ends; and (3) aligning the two arrays to each other using batch, active alignment. Batch alignment succeeds to the extent that each array is collinear, so the collinearity achieved in processes (1) and (2) is crucial. Typically, collinearity of ±1 μm or better is achieved for each array. When such arrays are batch aligned using the techniques described herein, the average coupling efficiency is about 88% as large as it would be if each laser-fiber pair were optimally aligned individually