In vivo verification of a 100 Mbps transcutaneous optical telemetric link

We report on an optical telemetric link capable of providing a high data rate at a low power consumption for the transcutaneous transmission of neural signals. The telemetric link is designed for operation as the interface between an implanted cortical array and an external receiver. By converting the digitized neural signals to a stream of infrared optical pulses, the optical telemetry wirelessly transmits the neural data through the skin. The implantable transmitter prototype PCB contains a VCSEL (Vertical Cavity Surface Emitting Laser) driver with a VCSEL glued onto its chip surface. For protection, the transmitter PCB is coated with a thin layer of PDMS. The external receiver utilizes a large-size PIN silicon photodiode followed by a shunt shunt feedback transimpedance amplifier, a limiting amplifier and circuitry for clock and data recovery. In vivo tests performed on an anesthetized sheep show that the link is capable of transmitting data at a speed of 100 Mbps with a bit error rate (BER) of 2× 10^-7 while consuming only 2.1 mW of electrical power.