Abstract: The present disclosure relates to a field of photonic computing and provides a photonic computing system including: a photonic computing unit configured to receive a first plurality of optical signals, wherein the first plurality of the optical signals represent a first set of values respectively. The photonic computing unit includes a plurality of weight modules, the weight modules represent a plurality of predetermined values respectively, and each of the weight modules corresponds to one of the predetermined values. Each of the weight modules includes: an optical input part configured to receive one optical signal of the first plurality of the optical signals, and at least one directional coupler. The weight module corresponds to one of the predetermined values to achieve the multiplication operation.