A light receiving module (200) is provided, including a beam contraction module (201), a multi-core multi-mode waveguide (202), and a detector (203). The beam contraction module (201) is configured to receive a first optical signal, and contract a mode spot of the first optical signal, to obtain a second optical signal. The multi-core multi-mode waveguide (202) includes a cladding layer (2022) and N waveguides (2021). The multi-core multi-mode waveguide (202) is configured to: receive the second optical signal, and concentrate energy of the second optical signal in a plurality of waveguides (2021) of the N waveguides (2021), to obtain a plurality of third optical signals. The detector is an array formed by N sub-detectors. A plurality of sub-detectors of the N sub-detectors are in one-to-one correspondence with the plurality of third optical signals. The plurality of sub-detectors are configured to receive the plurality of third optical signals, to obtain a plurality of electrical signals based on the plurality of third optical signals. An area and an angle for receiving the second optical signal can be increased by using the multi-core multi-mode waveguide (202), to reduce impact of offsets of a center position and a pointing angle of a light spot on light receiving and detecting efficiency, and reduce a power jitter.