Design of an optical interconnect for photonic backplane applications

A compact alignment-tolerant interconnect has been developed for use within a prototype modulator-based free-space photonic backplane. The interconnect design encompasses several unique features. Microlens arrays are used, and several beams share each microlens by clustering the optical input-output in a small field about the optical axis of each lens. For simplifying the layout, the optical input and output of each smart-pixel array are clustered separately, thereby allowing a Fourier plane patterned-mirror array to be used in the beam-combination optics. This allows a suitable balance between high interconnection densities and reasonable optical relay distances between adjacent boards to be achieved. The primary advantages of this scheme are the simplicity of the optical design and its alignability, making it ideally suited for high-density interconnection applications.