Cross-layer TCP flow aware model for energy efficient use of FP lasers in passive optical networks

In the access part of the network, passive optical networks (PON) are the top priority due to their robustness and large data carrying capacity. The customer premises equipment consumes 65% of the total power. We propose a cross layer model for saving energy in the optical network units (ONU). Our solution involves analysis of TCP traffic by extracting session information from the traffic and determining idle times between sessions. These idle times allow us to turn-off the laser diodes in ONUs at the user end. The Fabry-perot laser diodes (FP) typically run on 10 mA of current and produce approximately 2.5 volts of output. By turning off the diode we intend to save energy for periods of time when there is no data to transmit. We also investigate the effects of turning the laser diode on off frequently on the diode itself. Our experimental data shows no significant degradation in the output power stability. Moreover, we can cumulatively save considerable amount of energy.