The utility model provides an optical module for receiving light in a digital coherent light transmit-receive mode. The optical module comprises two optical fibers used for inputting signal light and local light; an optical signal processing circuit, wherein one terminal of the optical signal processing circuit is connected with the two optical fibers, the signal light and the local light are interfered and output from other terminals opposite to the one terminal, and a part of the input signal light is diverted and output from a given site of the one terminal; a signal output part used for photovoltaic conversion of light output from the other terminals of the optical signal processing circuit and then outputting the light as signals; and a monitor PD disposed on the optical path of the signal light and used for monitoring energy of branched signal light. The optical signal processing circuit is provided with a base plate, an optical waveguide layer and a substrate, a light shield member is disposed on the edge face of the optical signal processing circuit that faces the monitor PD, and the whole edge face of the base plate, a clad layer and the substrate, and the light shield member includes an aperture unit aligned with the given site where the diverted signal light is output.