Transcutaneous optical telemetry system for a totally implantable artificial heart

-Investigations of optical coupler and modulation

Abstract

Transcutaneous telemetry system without corrosion of the skin is indispensable for driving TAH. Several informations inside body can be transmitted to outside body using transcutaneous optical coupler constructed by LED embeded under the skin and PD attached to the outer surface of it. In this paper we investigated optical transmission characteristics of the skin and optimum direction angle of LED to construct fine transcutaneous optical coupler against dislocation between the optical devices. We found that in the optical transmission through several parts of the skin of goat and cow, the lights of wavelengths of 850nm and 1, 100nm are attenuated smaller than the other wavelengths, and in case of the skin thickness of 4mm the direction angle of LED of 23.5 degrees is most optimum against the eccentric deviation between the optical devices. And we also investigated modulation method to improve information transmission characteristics. We used the ASK modulation method, and evaluated the information transmission.