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

An optical exchange linked one or more optical fibers including a single optical fiber to at least one line termination device in a passive optical network, the exchange comprising;

• means for transmitting a phase-modulated, NRZ-DPSK-formatted downlink optical data signal;
• means for converting a phase-modulated, NRZ-DPSK-formatted uplink optical data signal into an amplitude-modulated, duobinary modulation-formatted uplink optical data signal;
• means for receiving the amplitude-modulated, duobinary modulation-formatted uplink optical data signal,
• wherein the phase-modulated, NRZ-DPSK-formatted downlink optical data signal and the phase-modulated, NRZ-DPSK-formatted uplink optical data signal are both transmitted over the single optical fiber.

In a passive optical network comprising an optical exchange the optical exchange comprising means for transmitting a phase-modulated, NRZ-DPSK-formatted downlink optical data signal and means for receiving phase-modulated, NRZ-DPSK-formatted uplink optical signal, a line termination device comprising:

• coupling means for dividing the optical power of the phase-modulated, NRZ-DPSK-formatted downlink optical data signal so as to obtain a first downlink optical signal and a second downlink optical signal;
• means for converting the first downlink optical signal into an amplitude-modulated, duobinary modulation-formatted optical data signal;
• and
• means for generating a phase-modulated, NRZ-DPSK-formatted uplink optical data signal from the second downlink optical signal,
• wherein the optical exchange and the line termination device are connected by one or more optical fibers including a single optical fiber,
• wherein the phase-modulated, NRZ-DPSK-formatted downlink optical data signal and the phase-modulated, NRZ-DPSK-formatted uplink optical data signal are both transmitted over the single optical fiber.

A method of transmitting a downlink optical data signal and of receiving an uplink optical data signal in a passive optical network comprising an optical exchange linked by one or more optical fibers including a single optical fiber to at least one line termination device of said network, the method comprising:

• transmitting a downlink optical data signal phase-modulated in NRZ-DPSK format;
• converting a phase-modulated, NRZ-DPSK formatted uplink optical data signal into an amplitude-modulated, duobinary modulation formatted uplink optical data signal;
• and
• receiving the amplitude-modulated, duobinary modulation-formatted uplink optical data signal,
• wherein the phase-modulated, NRZ-DPSK-formatted downlink optical data signal and the phase-modulated, NRZ-DPSK-formatted uplink optical data signal are both transmitted over the single optical fiber.

A method of receiving a downlink optical signal and transmitting an uplink optical data signal in a passive optical network comprising an optical exchange linked by one or more optical fibers including a single optical fiber to at least one line termination device of the network, the method comprising:

• dividing the optical power of the transmitted downlink optical data signal so as to obtain a first downlink optical signal and a second downlink optical signal;
• generating a phase-modulated, NRZ-DPSK-formatted uplink optical data signal from the second downlink optical signal;
• transmitting the phase-modulated, NRZ-DPSK-formatted uplink optical data signal;
• converting the format of the downlink optical data signal from a phase-modulated, NRZ-DPSK-format to an amplitude-modulated duobinary modulated format;
• receiving the amplitude-modulated, duobinary-formatted downlink optical data signal,
• wherein the phase-modulated, NRZ-DPSK-formatted downlink optical data signal and the phase-modulated, NRZ-DPSK-formatted uplink optical data signal are both transmitted over the single optical fiber.