The use of Field Assembly Optic Connector is to put a piece of bare fiber into the ceramic ferrule, and after grinding the top end, the operator cuts the other end of the fiber and inserts it on the spot. As the optical fiber is embedded in front of the embedded structure, the factory will polish and fill the interface with matching liquid. The advantage of this is that it does not rely too much on the flatness of the fiber end face cutting, which reduces the requirement for the proficiency of the operator. Since the end face of the joint is pre-polished, the product structure can achieve better insertion loss (less than 0.5db) and return loss (above 45db) indicators, with better reliability and stability