Frequency domain interleaving for dense WDM passive optical network

Abstract

In this work, we introduce a new concept of frequency interleaving applied to passive optical networks based in Dense Wavelength Division Multiplexing (DWDM). In order to explore colorless ONUs approach, a single and centralized optical source is used to create the interleaved wavelengths for the downstream and upstream path. In this case, frequency comb generation implemented by recirculating frequency shifting technique allowed the creation of all the wavelengths used in each path. The reception operation is accomplished by introducing, at the ONU side, a combination of a set of optical passive elements. The system with 4 × 12.5 Gbit/s NRZ-OOK (Not Return to Zero - On-Off Keying) modulation format were simulated through 20 km of standard single mode fiber link in both transmission paths. In order to guarantee a high quality optical frequency comb source, the optical carrier-to-noise-ratio (OCNR) was evaluated as well as BER (bit error rate), to analyze the system performance. All devices models and simulations were performed in Matlab environment.