A detailed study on the effectiveness of three proposed optical orthogonal frequency-division multiplexing (OOFDM) adaptive loading algorithms (ALAs) is conducted, addressing, for the first time, a number of crucial issues related to OOFDM directly modulated laser-based intensity-modulated and direct-detected passive optical networks (PONs). The ALAs include the power loading (PL), bit loading, and bit-and-power loading (BPL) algorithms. It is shown that in comparison with the most sophisticated BPL algorithm, the simplest PL algorithm is effective in escalating a single-channel OOFDM PON performance to its maximum potential. On the other hand, for multi-channel OOFDM PON and when employing a large number of subcarriers and high digital-to-analog/analog-to-digital converter sampling speed, the BPL algorithm should be adopted. The utilization of the three ALAs can also extend the optimum clipping ratio range up to at least 3 dB compared to a conventional identical modulation scheme.
© 2012 OSA
Original Manuscript: January 9, 2012
Revised Manuscript: May 28, 2012
Manuscript Accepted: August 20, 2012
Published: September 24, 2012
E. Giacoumidis, A. Kavatzikidis, A. Tsokanos, J. M. Tang, and I. Tomkos, "Adaptive Loading Algorithms for IMDD Optical OFDM PON Systems Using Directly Modulated Lasers," J. Opt. Commun. Netw. 4, 769-778 (2012)