MultiCAP modulation for high spectral efficiency transmission over SI-POF

Plastic optical fiber (POF) has been considered as a low-cost alternative to traditional copper cabling for indoor and industrial networks. Large core step index plastic optical fibers (SI-POFs) are lightweight and robust with a safe and an easy installation. These advantages are coupled with high attenuation and dispersion that have so far limited its use to short reach and low bit rate applications. Nowadays, new multimedia services require higher data rates and longer distances, and complex modulation techniques, such as pulse amplitude modulation (PAM) or carrierless amplitude phase (CAP) modulation, have been proposed to reach these new requirements. However, both modulations are very sensitive to non-flat spectral links, such as the POF one, and require very complex equalizers. To solve this important issue, we propose a multiband approach to CAP signalling (MultiCAP), where the CAP signal is divided into smaller bands. MultiCAP have the same advantages of CAP such as lower peak-to-average power ratio (PAPR) and high spectral efficiency, and, additionally, the CAP filters become easier to realize, since the frequency bands covered by each pair of filters are narrowed down. Another advantage of MultiCAP is the possibility to use different modulation orders in each band to accommodate different bitrate or to compensate the dispersion or losses in the link.