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Single diffractive lenses with submicrometer feature sizes are realized with binary, multilevel, and blazed reliefs using computer-aided design methods, three-dimensional (3D) profiling algorithms, direct write e-beam lithography, reactive ion etching, antireflection coating, and wafer dicing. Depending on the relief profile, maximum diffraction efficiencies of more than 70% for lenses with a high numerical aperture of 0.5 were measured and aberration-free imaging was observed. In order to enhance the diffraction efficiency we present a method for obtaining Fresnel grating lenses and a flexible 3D shaping of the resist mask for the dry etch process.

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Optical clock signal distribution has widely been discussed to be an attractive way to reduce the clock skew in high speed digital systems. For short interconnection lengths, especially for chip level clock distribution, free space systems using diffractive optical elements (DOEs) have specific advantages. The optoelectromc pathway described in this paper consists of a GaAs laser diode, a microetched silicon mirror, a facetted diffractive element and silicon photodiodes.The key element of the clock distribution demonstrator is the diffractive element (the mirror), which matches set-up requirements like compactness, an off-axis geometry and use of an unshaped laser diode beam. The diffractive mirror is computer generated, it is direct E-beam written and its diffraction pattern is dry etched into the surface of a silicon wafer. It is shown that the whole set-up meets the demands of alignment accuracy in an excellent way. This is achieved by the very good imaging characteristic of the DOE and by an alignment technique based on precision mounting of microetched silicon components.

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