An adaptive device was newly developed for a synaptic connection circu
it with learning ability. A synaptic weight was varied during operatio
n when an optical correction signal was applied. The synaptic weight w
as varied from -0.7 to +0.7 proportionally to the applied duration of
the optical correction signal and kept in a nonvolatile manner. It was
clarified that artificial self-organising neural networks can be real
ised using the adaptive device.