Optoelectronic packages in the active optical cable market are often composed of very small lens (among other components). These lenses can be used to reflect, filter or focus light. MOEMS and MEMS utilize lenses to manipulate its systems' desired function. MOEMS devices are fundamentally "micro mirrors".
Applications requiring ultra high placement accuracies of ±1μm to ±3μm are resurfacing in several optoelectronic applications such as Arrayed Laser Print Head and Multi-Channel Optical Communication products. Some of the higher performance optical communication products rely on P-side down laser attachment.
P-side down laser attachment using gold-tin (AuSn) eutectic solder is a mature process used extensively for long haul and metro distance laser transmission modules . The P-side down laser has traditionally been assembled using singulated heat spreaders with a pulsed heat in situ reflow stage where each eutectic assembly is built in the same XY location on the machine tool. This allows for optimization of placement accuracy and attachment quality at a given XY location.
Continued work in P-side down laser attachment has expanded the technology to Wafer Scale. This technology shifts away from singulated submounts to bonding lasers directly on a wafer matrix of submounts. Laser assembly design considerations for light output, component heat flow, power limits, and reliability are significantly affected by specific geometry, materials, and interconnect processes.