We propose a novel all-optical buffer and shaper based on the adjustable power transferring characteristics of the complexmodulated long-period-grating coupler (CM-LPGC) and the multiple circulations of the self-closed fiber loop. By turning on the external optical pumps, the signals can be stored by utilizing the nonreciprocal power transferring of the CM-LPGC. When the buffer time is satisfied, the signals can be extracted discretionarily by turning off the external optical pumps. In addition, by controlling the spectral bandwidth of the CM-LPGC, the temporal rectangular pulse can be obtained by reshaping the Gaussian input signal.