Patent ID: 8554078

Claim:
An optical network comprising: a first passive optical network optical line terminal arranged to transmit a first optical signal at a first wavelength, coupled to a first port of a first optical filter arrangement; a second passive optical network optical line terminal arranged to transmit a second optical signal at a second, different wavelength, coupled to a second port of the first optical filter arrangement; an optical coupler connected between the second passive optical network line terminal and the second port of the first optical filter arrangement, for coupling a plurality of optical signals at a predetermined set of wavelengths from a third optical line terminal into said second port; and a passive optical distribution node for connection to a plurality of optical network terminations, coupled to a third port of the first optical filter arrangement for distribution of optical signals between the optical line terminals and said plurality of optical network terminations, wherein the first optical filter arrangement is arranged to pass optical signals at said first wavelength between the first port and the third port and to block optical signals at said second wavelength and said predetermined set of wavelengths between the first port and the third port, and the first optical filter arrangement is further arranged to pass optical signals at said second wavelength and said predetermined set of wavelengths between the second port and the third port and to block optical signals at said first wavelength between the second port and the third port; and the second optical signal is at a faster rate than the first optical signal, and the second wavelength and the predetermined set of wavelengths are within an amplification band of a doped fibre amplifier.