Passive alignment in optoelectronic packaging

Passive alignment is the method of optically aligning devices to each other without having to operate them in order to simplify and speed the assembly process to reduce cost. Various optical and mechanical methods have evolved for doing this. When comparing the methods, the mechanical methods of alignment offer the advantage that they do not require expensive optics and staging to achieve precise alignment, because the burden of the precision is with the fabrication of the parts to be aligned. Conversely, the optical method of alignment offers the advantage that the parts to be aligned do not have to be precise, because the burden of precision will be held by the expensive staging and optics of the alignment equipment used in production. The challenge in achieving passive alignment of single-mode optics is far greater than it is for multimode, but the payoff can be substantial because the dominant cost of packaged single-mode components is the optical alignments