This paper proposes a kind of modulation architecture for wavelength-division-multiplexing passive optical network(WDM-PON)employing optical differential quadrature phase shift keying(DQPSK)downstream signals and two different modu-lation formats of re-modulated upstream signals.At the optical line terminal(OLT),10 Gbit/s signal is modulated with DQPSK.At the optical network unit(ONU),part of the downstream signal is re-modulated with on-off keying(OOK)or inverse-return-to-zero(IRZ).Simulation results show the impact on the system employing NRZ,RZ and carrier-suppressed return-to-zero(CSRZ).The analyses also reflect that the architecture can restrain chromatic dispersion and channel crosstalk,which makes it the best architecture of access network in the future.
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