Simultaneous transmission of high-speed point-to-point dataand double broadcast servicesin a WDM-PON system with source-free ONUs

摘要

We propose that double broadcast services can be overlaid over high-speed point-to-point downlink data in a WDM-PON with source-free optical network units(ONUs).In the optical line terminal(OLT),a set of single-drive Mach-Zehnder modulators(MZMs)are driven by downlink point-to-point data to generate a differential phase-shift keying(DPSK) format.The downlink DPSK signals from different wavelengths are multiplexed and then fed to a followingdual-parallel MZM(DPMZM)as a double broadcast services transmitter.The broadcast service_l is an optical carriersuppression(OCS)format,while the broadcast service2 is an inverse return-to-zero(IRZ)forma.After the transmission,at each ONU, the optical signals are separated by an optical filter.The filtered OCS signal is detected to retrieve thebroadcast service_1.The DPSK/IRZ signals are split into three parts,one part is detected by an IRZ receiver to recoverthe broadcast service2,the second part is detected by a DPSK receiver to retrieve the downlink data and the third part isre-modulated by the upstream amplitude shift keying(ASK).We also perform an experiment to verify the feasibility ofthe proposed scheme, where the power penalties of less than 1.5 dB are obtained after 25-km transmission with 1.25-Gb/s data rate