A cascaded all-optical buffer with large dynamic delay based on polarization rotation of a gain-transparent semiconductor optical amplifier is proposed and demonstrated. The analysis and experimental results indicate that the pulse distortion and pattern effect can be fully improved, and the amplified spontaneous emission noise accumulation can be inhibited effectively as well; the data packets are stored for six round-trips in buffering units 1 and 2, respectively, corresponding to a delay time as long as 33 μs. The proposed buffering scheme can be regarded as an effective reference to the study work of all-optical buffer.