It is proposed that the feasibility of a high-speed data link using optical transmission across the skin be investigated. Cochlear implants having increased numbers of channels and more rapid rates of pulse delivery require data rates higher than combined RF coil links for data and power can presently provide. Selected wavelengths of light penetrate skin and many other tissues to the degree necessary for communication between surgically implanted devices and an interface on the surface of the skin. In this project the limitations for such a two-way, transcutaneous optical data link will be examined in term of optical wavelengths, physical positioning of components, and tissue properties. A measure of the errors occurring in data transmission will be obtained for these parameters so that the maximum data transmission rate for a given error level can be estimated. This technology has potential use in a number of biomedical areas, especially for neural and neuromuscular prostheses. PROPOSED COMMERCIAL APPLICATION: Possible commercial applications of this research are in the biomedical area. Most immediate is a high-speed, two-way data link to implantable components in a new generation of cochlear prosthetic systems. This link will make possible increased numbers of functional channels and more rapid updates for each channel, i.e., a higher information flow to the patient. Furthermore, this technology has potential for use with other surgically implanted biomedical systems including those for functional electrical stimulation of muscles, visual prostheses, cardiac assist devices, molecular delivery systems and other applications where external communication or control is needed.