Patent ID: 6038047
Filing Date: 2000-03-14
Classification: H04B

Abstract:
A digital optical telecommunication method comprising the steps of:receiving a first electric signal carrying a piece of information at an optical transmission station and generating a digital modulated optical signal at a predetermined wavelength, corresponding to said electric signal;feeding said modulated optical signal to an optical-fibre line having a predetermined unitary-attenuation value at said wavelength; andreceiving said modulated optical signal transmitted from said optical-fiber line at a given optical-power level, at an optical receiving station, converting the received optical signal to an electric form and at the optical receiving station generating a second digital electric signal;characterized in that:said step of generating a modulated optical signal comprises coding said piece of information of said first electric signal in a sequence of elementary information units individually associated with said piece of information, said units following one after the other according to a first predetermined cyclic time rate, andsaid step of generating a second digital electric signal comprising detecting in said converted signal, an electric signal having a second cyclic time rate higher than said first cyclic time rate and recognizing in the detected signal, the phase of an electric signal at said first time rate by comparing a receiving sequence of elementary information units with at least one reference sequence and verifying the correspondence of the result of said comparison at a given condition.