An optical-signal vestibular-nerve stimulation device and method that provides different nerve stimulation signals to a plurality of different vestibular nerves, including at least some of the three semicircular canal nerves and the two otolith organ nerves. In some embodiments, balance conditions of the person are sensed by the implanted device or external device, and based on the sensed balance conditions, varying laser nerve-stimulation signals are sent to a plurality of the different vestibular nerves.