非线性光纤环形镜（NOLM）在不同抽运条件下具有不同的连续波开关特性，当单抽运NOLM在抽运峰值功率大于开关阈值功率时具有反转抽运脉冲峰的特点，在抽运脉冲上升与下降沿处各产生一个脉冲输出；当使用双脉冲抽运在两抽运脉冲除峰值功率和波长不同外其他参数一致时，透射输出由两个脉冲的峰值功率差决定，具有脉冲峰值功率比较作用。基于NOLM的这两个特性设计了全光分离两光功率水平信号的方案。利用光子学仿真软件进行了数值仿真，结果显示二光平信号被成功分离，并分别加载到不同波长上。实现了高功率级无基座脉冲输出，表明该方案也具有消除脉冲基座的能力。

The switching characteristics of nonlinear optical fiber-loop mirror (NOLM) for continuous wave are different under different pumping conditions. When the pump peak power is greater than the switching threshold power, it is found that the transmitted waveform of single-pumped NOLM has the feature of inverting pump pulse peak and one transmitted pulse is generated respectively at the corresponding rising and falling edges of the original pump pulse. The double-pumped NOLM has the function of comparing pulse peak power of two input pump pulses which have the same parameters except for the power and wavelength, and output pulse power is determined by the deviation of the peak power of two pump pulses. Based on two above characteristics of NOLM, a scheme is designed for all-optically separating the pulses from the same input signal with two-level power. Numerical simulations are executed by using photonics simulation software. The results show that two-level power signal is separated successfully, and output signals are loaded to different wavelengths respectively. No pedestal is observed at the separated output higher-level power pulses. So the scheme also has the ability to eliminate pulse pedestal.