Optical computing device, system and computing method

The invention provides an optical computing device, system and computing method. The optical computing device comprises an input loop, an output loop and at least one LCU. The input loop comprises at least one optical splitter and a first optical switch; the output loop comprises at least one coupler and a second optical switch; each optical splitter is connected with one coupler through the corresponding LCU; the first optical switch is used for controlling signal input; the second optical switch is used for controlling signal output; the optical splitter is used for extracting part of signals from the input cycle and sending the signals to the corresponding LCU; the LCU is used for carrying out linear operation on the received signal and sending a linear operation result to the coupler which is correspondingly connected with the LCU; and the coupler is used for accumulating the received linear operation result and the linear operation result stored in the output loop, and obtaining and storing a new linear