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Programmable variable delay lines have been developed, so as to delay packets in variable durations by combining several lengths of FDLs in optical packet switch. In practice, two-stage switch with this programmable variable delay lines has been proposed. This switch has two buffers. One is the programmable variable delay lines (look-ahead buffer). The other is the fixed FDLs that re-input a packet from the output to the input (loop-back buffer). The switch can foresee following packets and avoid contentions effectively by using two buffers. However, existing studies only focus on the look-ahead buffer and intelligent usage of the loop-back buffer is actually out of concern. In this paper, a packet transfer scheduling method in the two-stage switch is proposed. The proposed method controls both the look-ahead buffer and the loop-back buffer cooperatively and improves the utilization of the switching process. The proposed method uses the loop-back buffer systematically and distributes traffics in the whole switch. The effectiveness of the proposed method is evaluated through simulation experiments.