We presents a semiconductor laser amplifier （SLA） with a three wavelength configuration

which works as a nonlinear element and realizes the OTDM demultiplexing function in an optical loop mirror. The simulation shows that its switching time can be less than 10 ps at the holding beam power of 1W

and therefore it has the ability of demultiplexing the signal of any channel from the 100 Gbit/s optical time division multiplexing （OTDM） pulse trains at the control power of 900 mW.