Self-aligned positioning of microoptical components by precision prismatic grooves impressed into metals

Grooves embossed into metallic substrates are proposed for self-aligned positioning of microoptical components like microlenses, optical fibers, glass rods with mirrors or filters, etc. As substrates, both ductile metals such as aluminum or copper, and hard alloys like CrNi steel can be used, which allows adaptation to requirements concerning thermal expansion coefficient, thermal conductance, hardness, mechanical strength, solderability, weldability, etc. Compared to other methods such as anisotropic etching in silicon substrates and LIGA, this technique offers more design flexibility and much lower investment cost and is well suited for medium production numbers. By the embossing process, the shape and surface quality of the embossing die are virtually transferred into the groove. The residual deviation between die and groove is in the order of 5-10 μm. The reproducibility is better than 5 μm, thus allowing self-aligned positioning with multimode fiber applications. Without reconditioning, several thousand embossing cycles can be made with the same die. The manufacturing of embossing dies is based on precision tooling techniques. The paper concludes with two application examples of optical communication components