High bit rate bidirectional passive optical network, associated optical exchange and line termination device

An optical exchange linked by at least one optical fiber to at least one line termination device in a passive optical network, said exchange comprising first means for transmitting a downlink optical data signal phase-modulated in NRZ-DPSK format and second means for receiving an uplink optical signal transmitted by said at least one line termination device, said optical exchange being characterized in that, the uplink optical signal being phase-modulated in NRZ-DPSK format, said exchange comprises, prior to said second reception means, second means for converting said uplink optical signal phase-modulated in NRZ-DPSK format into an optical data signal amplitude-modulated in duobinary modulation format, said second reception means being able to receive said uplink optical signal amplitude-modulated in duobinary modulation format.

A line termination device in a passive optical network comprising an optical exchange linked by at least one optical fiber to said line termination device of said network, said exchange comprising first means for transmitting a downlink optical data signal phase-modulated in NRZ-DPSK format and second means for receiving an uplink optical signal, said line termination device comprising coupling means for dividing the optical power of the transmitted downlink optical signal so as to obtain a first and a second downlink optical signal, first means for receiving said first downlink optical signal and second means of generating and transmitting an uplink optical signal from said second downlink optical signal, characterized in that said line termination device comprises means for converting said first transmitted downlink optical signal phase-modulated in NRZ-DPSK format into an optical data signal amplitude-modulated in duobinary modulation format, said first reception means being able to receive said amplitude-modulated downlink optical signal;

• wherein:
• said means for generating and transmitting an uplink optical signal are able to generate and transmit an uplink optical signal phase-modulated in NRZ-DPSK format from said second downlink optical signal.

A method of transmitting a downlink optical signal and of receiving an uplink optical signal in a passive optical network comprising an optical exchange linked by at least one optical fiber to at least one line termination device of said network, said method comprising a step for transmitting a downlink optical data signal phase-modulated in NRZ-DPSK format and a step for receiving an uplink optical signal, said method comprising, prior to the step for reception of an uplink optical signal, a step for conversion of said uplink optical signal phase-modulated in NRZ-DPSK format into an uplink optical signal amplitude-modulated in duobinary modulation format.