Cost effective OLT arrangements in 40 Gbps WDM-PON using AWG with a single laser

Abstract

In this paper, we upgraded the optical line terminal (OLT) of the optical access network for 40 Gbps by proposing a cost effective OLT based on cascaded model of phase modulator and arrayed waveguide grating for wavelength division multiplexed passive optical network (WDM-PON). The conventional setup at OLT side of WDM-PON system is replaced with a new arrangement containing single laser source in cascade with phase modulator and AWG, whereas the phase modulator is tailored with RF source. The phase modulator generates multicarrier signal and AWG splits the signal into multiple single wavelengths based on its routing configurations. AWG is actually used as a passing band periodical filter that routs the input wavelengths to four outputs depending on its free spectral range. Across each routed wavelength, differential phase shift keying is used in downlink transmission for 10 Gbps, while intensity modulation is employed in the uplink transmission based on off-keying. 40 Gbps full duplex transmission via 20 km fibre span is successfully achieved with minimum power loss and effective results. Transmission performances are examined with negligible power penalties, better Q-factors, handsome eye openings and good eye heights, which confirm the deployment of proposed arrangement in the next generation access network.