Optocoupler is an electronic component which transmits electrical signals between two independent circuits. An SSR is an electrical signalling system that triggers or disconnects when a specific external force is added to its operating terminals.
Optocoupler vs solid-state Relay (SSR) – what are the differences?
SSR is used as an electronic switch to control the flow of AC or DC electricity. The solid-state relays are built on opto-coupling technologies since they will provide high resistance and insulation between the input and output circuits. Both of the devices transmit signals while being electrically separated, although there are major variations.