LTCC toolbox for photonics integration

In photonic module integration, optoelectronic chips, micro-optical elements and integrated circuits are integrated into functional components, sub-assemblies, modules and systems. The building blocks of the photonic
system must be fabricated by the use of cost-efficient, reproducible, well-established, high-volume manufacturing technologies. The reliability of the system as well as the tolerances of device alignment are key issue in the integration. We have developed a Low Temperature Co-fired Ceramics (LTCC) toolbox for photonic integration. The primary aim was to process co-fired 3D structures, such as, grooves, cavities, holes, bumps and alignment fiducials for the passive alignment of photonic devices. LTCC provides means for full 3D integration. The tolerances of the alignment structures are typically ±5µm and in some specific cases ±2µm. LTCC structures provide means for the passive alignment of multimode fiber, for example. With Monte-Carlo tolerancing tools, we can simulate and optimize the performance of the system and estimate manufacturing yield in volume production. Thermal management by the use of thermal vias is a well-established technique; liquid cooling channels in the LTCC substrate provide efficient means for high-power laser cooling. LTCC provides
inherently hermetic substrate allowing the possibility for hermetic encapsulation. High-speed ICs as well as millimeter-wave circuits can easily be integrated into the LTCC substrate. Novel materials allow the fabrication of advanced systems, especially, for millimeter-wave operation.