Sol-gel replication of optical components suited for surface mount assembly

Abstract

Optical microsystems, which can be fabricated using replication technology and assembled using optical surface mounting techniques, can offer compact, cost-effective solutions for applications in optical communication, metrology, sensors, illumination and displays. Especially adapted to the needs of mid-size volume production of a few hundred to thousands modules is wafer-scale replication. The fabrication of single micro lenses or lenslet arrays on wafer substrates and the wafer-scale replication of such lens arrays for optical microsystems in sol-gel materials is under development as a cost-effective alternative to lens fabrication in glass. For an optical microsystem with a compact module for laser beam forming, wafer-scale, singlesided and double-sided replication has been developed to fabricate refractive or diffractive optical elements onto glass substrates. Combined opto-mechanical modules have been UV-cast-replicated from a sol-gel master in a single step. In addition, step & repeat replication can be employed for the fabrication of large arrays of custom specific lenses. Replication accuracy of better than a wavelength has already been achieved for refractive lenses with 50 µm SAG. Finally, diced optical components from the replicated wafers will be used for the manufacturing of micro-optic systems. A six-axis robot motion, automated optical alignment and laser-reflow soldering method is used to assemble the photonics modules. This method, called TRIMO-SMD (three-dimensional miniaturized optical surface-mounted device), is currently being made commercially available by Leica Geosystems AG.