An LTCC optical microfluidic system with glass fibers incorporated before firing

The paper presents a LTCC based microfluidic detector which can be used for measure of an optical absorbance or transmittance. Novelty in this structure is incorporate a glass fibers before ceramics cofiring. Up to now integration of optical fibers with a structure fabricated from a standard LTCC green tape was very difficult. Shrinkage of the LTCC during cofiring process, causes tensions of the fibers and finally destroy the structure. For this reason up to now the optical fibers are glued to the LTCC after cofiring process. New Heraeus Heralocktrade 2000 with near zero shrinkage, enable integration of the fibers before sintering of the ceramic. Presented structure involved a microfluidic channel and two fibers which were input and output for optical power. Three lengths of the channel was made - 30 mm, 25 mm and 22.5 mm, where the length between ends of the fibers was 10 mm, 5 mm and 2.5 mm, respectively. That kind of structure is very promising because it is enable to made integrated MOEMS which contains fibers embedded in LTCC green tape. The tests show that the fibers provides light which level of the optical power on the output is high enough to detect the changes.