Long reach colorless WDM OFDM-PON using direct detection OFDM transmission for downstream and OOK for upstream

Abstract

Here we have proposed a novel architecture of wavelength division multiplexed orthogonal frequency division multiplexing (OFDM)-passive optical network (WDM OFDM-PON) which is capable of transmitting 10 Gbps data both in downstream and upstream directions up to 50 km. Here direct detection OFDM is used for downstream unicast transmission and simple on–off keying data is used for upstream unicast transmission. OFDM eliminates inter-symbol interference through use of a cyclic prefix also provides good protection against co-channel interference and impulsive parasitic noise. Since delay interferometer (DI) acts as a optical equalizer and vestigial sideband filter hence a DI is used at central office for successful transmission of 10 Gbps upstream data up to 50 km using reflective semiconductor optical amplifier at optical network unit (ONU) having bandwidth of 1.5 GHz. Since no extra laser source is used at ONU and downstream data is further used for upstream data modulation so colorless scheme is implemented. Simulation is performed for all downstream and upstream channels having data rate of 10 Gbps with a transmission distance of 50 km having acceptable performance.