The good quality cascaded multiwavelength chirped fiber Bragg grating (MFBG) were written using scanning mask/fiber technique.The MFBG had low PMD (1.2ps) and low insertion loss (4dB).Dispersion of 4×10Gbps WDM transmission over 640km of G.652 fiber was compensated using MFBG with all channels' power penalty less than 1.5dB.We had studied fluctuation of power penalty when source wavelength changed ±20GHz around ITU-T center.The fluctuation was less than 0.2dB.The experiment showed that overall penalty was proportional either to the number or to the square root of the number of the MFBG employed along the link.Ripple of overall MFBG delay and fluctuation of overall MFBG reflectivity were not simply piled up

but related with the place of MFBG and line amplifier gain.