A detection device includes an optical coupler, a scattering component, a detector, and a processor. The optical coupler is configured to: receive a to-be-detected light beam, and couple the to-be-detected light beam to the scattering component. The scattering component is configured to: scatter the to-be-detected light beam, and output a plurality of scattered to-be-detected light beams at different angles in time division mode to the detector. The plurality of scattered to-be-detected light beams are in one-to-one correspondence with the plurality of angles. The detector is configured to detect a plurality of different regions of the plurality of scattered to-be-detected light beams, to obtain a plurality of electrical signals. The detector is further configured to transmit the plurality of electrical signals to the processor. The processor is configured to compute the plurality of electrical signals to obtain related information of the to-be-detected light beam.