Realization of Multi-fiber Ferrule Mold Inserts Fabricated by the LIGA Process

摘要

This paper presents a micromachining technique to solve the precision machining difficulty for multi-fiber ferrule production. The LIGA technology is applied to make 1.2 mm thick V-groove mold inserts with dimensional tolerance 1 μm. It starts with X-ray mask fabrication, x-ray exposure, Ni-Co electroforming, and planarization to complete the metallic ferrule mold inserts. X-ray mask is developed here in low cost and accessible in Taiwan. The absorber thickness can be achieved to 30 μm in straightness. The single x-ray exposure can generate 1.2 mm thick PMMA after development process. This development proves the feasibility of many applications in x-ray micromachining. In the optical fiber passive components, connectors play a joint role in the whole system. Ferrule is the key part of a fiber connector. Since the development of the LIGA technology, high precision micro-components such the ferrule is considered to be applied. All multi-fiber ferrules require the same accuracy of pitch distance between two channels. The mold insert for ferrule fabrication becomes the most important part. Conventional precision machining has certain limitations on machining micro-components due to machining tool size and material wears. The LIGA technique can overcome these problems. It utilizes X-ray to penetrate polymer material and create molds, then applies electroforming to make metallic molds. These molds can be applied for molding process in mass production.