A 2.048 Mb/s Full-Duplex Free-Space Optical Transceiver IC for a Real-Time In Vivo Brain–Computer Interface Mouse Experiment Under Social Interaction

This paper presents the first free-space optical transceiver IC for social, psychological brain–computer interface experiments with multiple mice. The proposed IC embedded in a head-mounted module (HMM) includes 8-channel neural recorder and a neural stimulator in order to record extracellular action potentials and local field potentials while injecting diverse waveforms of monophasic intracranial stimulation current into the medial forebrain bundle for the activation of the nervous system. The HMM implanted on a mouse transmits the neural recording data to an optical base station by using a mandatory 591/624-nm (amber/red) visible behavior tracking LED as an optical transmitter to save power. The HMM is controlled simultaneously via a 940 nm infrared optical downlink to reduce interference to the visible optical uplink. The proposed IC fabricated in a 0.18- $\mu \text{m}$ HV BCDMOS process consumes 90 $\mu \text{W}$ while achieving a 2.048-Mb/s transmission rate.