Abstract: A long period fiber grating(LPFG) is a wavelength seletive filter developed in recent years.According to its behavior of wavelength dependent loss,a LPFG is used as wavelength division demultiplexer for 1310nm/1550nm wavelength division multiplexing(WDM) system.By means of groove curving with electric arc discharge,several LPFGs are fabricated.Ideal spectra of LPFGs are obtained by controlling the process of electric arc discharge and the period and the length of LPFGs.The results show that insertion loss of pass channel is able to be less than 0.5dB,20dB loss bandwidth of rejection band is nearly 15nm,and that isolation of neighboring channel is about 25dB.