OBI reduction and optical power budget enhancement in OFDM-PON system using spreading code in electrical domain

Orthogonal frequency division multiplexing based passive optical network (OFDM-PON) gives better performance in high speed optical access networks because of its greater resistance to optical fiber dispersion and high bandwidth efficiency. Optical beating interference (OBI) is one of the main source of impairment which occurs in upstream direction. This paper proposes to use CDM/OFDM based PON architecture to reduce OBI in upstream and also improves optical power budget. In the analysis, no optical dispersion compensation has been used and all system related impairments have been considered for amplitude modulation/direct detection (AM/DD) optical communication system. Results depict that with BER value of 10−3, there is 8.1 dB gain in signal-to-noise ratio (SNR) and 5 dB, 9.5 dB improvement in optical power budget in downstream and upstream respectively. There is also 4.5 dB reduction in OBI in upstream direction with CDM/OFDM-PON system as compared to OFDM-PON system.