Design of a High Speed Transcutaneous Optical Telemetry Link

In some neural prosthetic applications there is a need for high bandwidth communication between an implanted device and an external device. For example, transmitting 100 channels of neural waveform data for a cortical prosthetic control system may require up to 40 Mbps for a 100 channel array. Due to the high bandwidth required and its relative immunity from interference, optical telemetry is the most realistic method for achieving a clinically robust transcutaneous communication system capable of achieving these data rates. It is proposed that a transcutaneous optical telemetry link design can be optimized to system level design parameters (power consumption, implant location, etc.) by having a quantified understanding of the different link level design parameters (optical power, lens size, tissue effects, transmitter-receiver alignment, etc.) and an understanding as to how those parameters interact, and will allow for a design guided by an a priori assessment of these parameters. Some of these design factors and their interactions are identified and described. One of these parameters, the tissue optical spatial impulse response is measured empirically for several porcine dermal tissue configurations, and it´s implications for device design tradeoffs are discussed