Patent ID: 8331786

Claim:
A transmission method of a WDM light in a WDM optical transmission system in which at least one band-limiting device is arranged on a transmission path through which the WDM light containing a plurality of optical signals of different wavelengths is propagated, and spectrum widths of the optical signals of respective wavelengths are limited when the WDM light passes through the band-limiting device, wherein for the optical signal of each wavelength contained in the WDM light, a spectrum component at a center wavelength thereof and a spectrum component in the vicinity of the center wavelength are selectively attenuated when the optical signal of each wavelength in the WDM light passes through a spectrum correction optical filter, to thereby perform the spectrum correction for increasing relative intensity of sideband components in the spectrum of each optical signal wherein the spectrum correction optical filter has transmission wavelength characteristics having a plurality of loss peaks at which transmittance thereof becomes minimal at wavelengths coincident with the center wavelengths of the respective optical signals.