Patent ID: 7747175

Claim:
An optical transmission method in a system for performing digital modulation of an optical pulse at a transmission end, propagating the pulse through an optical fiber transmission line, and converting the pulse to an electric signal by a photoreceiver, wherein the optical transmission method comprises: propagating the optical pulse which has time-domain waveform equal to an envelope profile of a frequency spectrum in a function form, and is transform-limited in which a product of the full width at half maximum and the frequency spectral width satisfies the Fourier limit conditions through the optical fiber transmission line; converting the time-domain waveform of the optical pulse transmitted through the optical fiber transmission line to a profile of the frequency spectrum by an optical Fourier transform circuit disposed before the photoreceiver, to generate a time-domain waveform whose shape is equivalent to the frequency spectrum of the signal before transmission and to eliminate all linear time domain distortions in the optical pulse by maintaining the envelope profile of the frequency spectrum before and after transmission in the optical fiber; and thereby, reproducing the original signal waveform at a receiving end without changing a group velocity dispersion D and a chirp rate K, which are parameters of the optical Fourier transform circuit, depending on the distortion.