TWDM-PON With Signal Remodulation and Rayleigh Noise Circumvention for NG-PON2

Abstract

We propose and demonstrate a 40-Gb/s (4 × 10 Gb/s) downstream and 10-Gb/s (4 × 2.5 Gb/s) upstream time-wavelength-division-multiplexed passive optical network (TWDM-PON) using signal remodulation. Here, a downstream differential-phase-shift-keying (DPSK) signal and an upstream remodulated carrier-suppressed single-sideband non-return-to-zero (CS-SSB-NRZ) signal are used, which are wavelength shifted to circumvent Rayleigh backscattering (RB). A silicon-based optical microring resonator (MRR) filter is preinstalled at the optical networking unit (ONU) to select the desired downstream wavelength and simultaneously demodulate the downstream DPSK signal, which is then detected by a monolithic-integrated germanium-on-silicon (Ge-Si) photodiode (PD). Using silicon-based devices could be cost effective for the cost-sensitive ONU. The future monolithic integration of a silicon filter, a silicon detector, and a silicon modulator in the ONU is also discussed. The characteristics of the preinstalled silicon-based MRR and the Ge-Si PD are discussed. Error-free transmission (bit-error rate (BER) <;10-9 ) is achieved in both downstream and remodulated upstream signals after propagating through 20 km of standard single-mode fiber (SMF).

Keywords

• Optical communications
• noise mitigation
• wavelength-division-multiplex passive optical network (WDM-PON)
• differential-phase-shift-keying (DPSK)