We propose a novel approach to realizing massively parallel optical interconnects based on commercially available multifiber ribbons with MT-type connectors and custom-designed planar-integrated free-space components. It combines the advantages of fiber optics, that is, a long range and convenient and flexible installation, with those of (planar-integrated) free-space optics, that is, a wide range of implementable functions and a high potential for integration and parallelization. For the interface between fibers and free-space optical systems a low-cost practical solution is presented. It consists of using a metal connector plate that was manufactured on a computer-controlled milling machine. Channel densities are of the order of 100/mm(2) between optoelectronic VLSI chips and the free-space optical systems and 1/mm(2) between the free-space optical systems and MT-type fiber connectors. Experiments in combination with specially designed planar-integrated test systems prove that multiple one-to-one and one-to-many interconnects can be established with not more than 10% uniformity error.

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For the ultraviolet (UV) photosensitive polyimide Probimide\circR 412 the dynamic behavior of induced refractive index changes due to indiffusion of water molecules is investigated by two different methods. On the one hand the optical waveguide anisotropy of thin films ( 2.41 µm) is determined in a transient experiment. On the other hand volume phase gratings in thick films ( 50–60 µm) are produced using holographic technique and the time dependence of the diffraction efficiency is monitored upon exposure to moisture. A crosslinking of the photosensitive polyimide can be achieved by UV illumination. Different sensitivities to moisture of exposed (crosslinked) and unexposed waveguide films are observed. This results in a change of the diffraction efficiency of a phase grating where exposed and unexposed regions alternate with each other. A simple model for the time dependence of the diffraction efficiency is presented and discussed.