Multiple-subcarrier optical communication systems with subcarrier signal point sequence

We propose a multiple-subcarrier (MS) optical communication system with subcarrier signal point sequence (SSPS). We use the SSPS having the large minimum value and the large Euclidean distances, so that the required d.c. bias is minimized and the error rate performance is improved. Note that in the proposed systems, the signal points having the larger minimum value are selected, while the signal points having lower peak to mean envelope power ratio (PMEPR) are selected in orthogonal frequency division multiplexing (OFDM) systems. Therefore, the signal point sequences good for OFDM with phase shifting by π radian are not necessarily good ones for MS optical communication systems. We show that the normalized power requirement and normalized bandwidth requirement of the MS-SSPS are smaller than those of the conventional MS systems.