Summary form only given. The optical period-doubling behavior is a nonlinear phenomenon observed in the laser with periodical modulation and saturated absorption. Recently, the semiconductor laser amplifier in loop mirror (SLALOM) has been extensively investigated as an ultrahigh-speed optical switch. Employing the SLALOM as an optical modulator, a mode-locked fiber laser has been demonstrated to generate a high-speed periodically optical pulse sequence for optical clock recovery. We present that optical period-doubling sequence which can be implemented in a fiber laser with a SLALOM with the low bias current of the SLA and a high optical power in the laser cavity. It has the potential applications in optical clock division. Comparatively, an optical periodical sequence has also been realized in this laser with the high bias current of the SLA and a low optical power in the laser cavity.