Agilecom's fiber array block units(FABU) utilize glass or silicon substrte and special fabricatiom technologies to achieve accurate fiber position and high reliability to meet different requirement. The FABU's are produced by placing fibers in precision glass v-groove substrate with another flat glass chip on top to form a 3-point contact with unique material and processing technologies. This enables packaging designers to match the thermal expansion coefficient of FABU with pigtail devces to achieve stress free performance and high reliability. The FABU end facet is polished accurately to required angle without fiber piston effect in a large working temperature range. These products meet or exceed Telcordia GR-CORE and GR-1221-CORE reliability qualification requirement.