Advanced packaging concepts for low-cost optoelectronic devices

The multiplication of fibre optic networks during the years 1980 to 2000 has led to the development of specific packaging designs for laser modules, e.g. butterfly or TO-can coaxial packages. Since the beginning of years 2000, it has become necessary for packaging designers to deal with new requirements in term of module size, cost, thermal and electrical performances, particularly concerning the BF design. From these new requirements, new quasi-standards have appeared: TO-based TOSAs, XMD, and so on... However, these solutions are still based on traditional technologies : die soldering, 3D active alignment, Kovar packages, laser welding, single-chip devices, discrete micro-optics., unsuitable for mass production at very low cost. Today, the challenge for optoelectronic industry is thus to achieve a mutation of the packaging and assembly concepts, similar to the one the microlelectronic industry has done thirty years ago, by introducing advanced packaging technologies in order to address emerging markets and need - such as FTTx and Very Short Reach optical links - at the targeted costs. This will be also done by pushing ahead the integration of several optical function on the same chip or optical board. Some of these emerging technologies, such as optical MCM (Multi Chip Module), passive alignment, new materials for thermal management, flip-chip hybridisation, are key concepts to manage this next step and are reviewed in this paper. These concepts have already been applied in some industrial products and should spread in the next years.