An annular optical buffer (100) and methods for storing and reading an optical signal are disclosed. The optical buffer (100) includes: a first bent straight-through waveguide (101a), functioning as a transmission bus of an optical signal; multiple optical delay waveguide loops (103), configured to temporarily store optical signals; multiple pairs of optical switches (102), whose quantity is the same as that of the multiple optical delay waveguide loops (103), where each pair of optical switches (102) are configured to control on and off of an optical paththat is ontwo arms of the first bent straight-through waveguide (101a) and two sides of an optical delay waveguide loop (103) corresponding to each pair of optical switches (102); a beamsplitter (106), configured to obtain a part of optical signal by splitting the optical signal that is input from an input end and transfer the part of optical signal to a controller (105) through a second bent straight-through waveguide (101c); a slow light effect waveguide (
