Preliminary study of transcutaneous optical coupling for implantable devices using GaAs solar cell

A transcutaneous optical coupling system was described for an implantable temperature sensor using GaAs solar cell as the power converter. A laser diode provides the optical power converter. The laser diode provides optical power to the GaAs solar cell (diameter of the effective area 3 mm) through different thickness of meat as the optical model of the skin. Converted electric power supplied to the temperature sensor and interfacing circuits (V/F converter and LED circuits). The output signal from LED was detected after passing through the meat by a photo-detector. Open circuit voltage and short circuit current were measured then calculated the converted power and efficiency at different optical power levels. The surface temperature of the solar cell was also measured. Converted power was decreased exponentially with increasing the thickness of meat. Approximately 37 mW of power was obtained at laser diodes's power 380 mW through about 0.6 mm thickness of meat while total power consumption of the implanted system was about 30 mW.