An annular optical shifter, wherein the optical shifter comprises: a first bent straight-through waveguide, n-shaped, connecting an input end and an output end of an optical signal, functioning as a transmission bus of the optical signal, and configured to transmit, to the output end, the optical signal input from the input end; multiple optical delay waveguide loops, each of which is arranged transversely and parallel on two arms of the first bent straight-through waveguide, wherein on and off of an optical path that is on two sides of each optical delay waveguide loop and the two arms of the first bent straight-through waveguide is implemented by using a pair of optical switches, and the multiple optical delay waveguide loops are configured to temporarily store the optical signal; multiple pairs of optical switches, whose quantity is the same as that of the multiple optical delay waveguide loops, wherein each pair of optical switches are configured to control the on and off of the optical path that is on the two arms of the first bent straight-through waveguide and the two sides of the optical delay waveguide loop corresponding to each pair of optical switches; and a controller, connected to each optical switch of the multiple pairs of optical switches by using a control signal line, and configured to receive an optical signal shift instruction sent by an external device, generate control signals according to the shift instruction, send the control signal to all optical switches on a specific side that are connected to a specific arm of the n-shaped first bent straight-through waveguide, and control on-off statuses of the optical switches on the specific side, so that the optical signal stored in the multiple optical delay waveguide loops are shifted up or down. a first bent straight-through waveguide, n-shaped, connecting an input end and an output end of an optical signal, functioning as a transmission bus of the optical signal, and configured to transmit, to the output end, the optical signal input from the input end; multiple optical delay waveguide loops, each of which is arranged transversely and parallel on two arms of the first bent straight-through waveguide, wherein on and off of an optical path that is on two sides of each optical delay waveguide loop and the two arms of the first bent straight-through waveguide is implemented by using a pair of optical switches, and the multiple optical delay waveguide loops are configured to temporarily store the optical signal; multiple pairs of optical switches, whose quantity is the same as that of the multiple optical delay waveguide loops, wherein each pair of optical switches are configured to control the on and off of the optical path that is on the two arms of the first bent straight-through waveguide and the two sides of the optical delay waveguide loop corresponding to each pair of optical switches; and a controller, connected to each optical switch of the multiple pairs of optical switches by using a control signal line, and configured to receive an optical signal shift instruction sent by an external device, generate control signals according to the shift instruction, send the control signal to all optical switches on a specific side that are connected to a specific arm of the n-shaped first bent straight-through waveguide, and control on-off statuses of the optical switches on the specific side, so that the optical signal stored in the multiple optical delay waveguide loops are shifted up or down.