Radio over Fiber- a New Communication Era: Future Broadband Wireless Access

Radio over Fiber is an innovating technology which provides provisioning for the flourishment of broadband wireless service which combines flexible optical routing and robust ROF transport technologies. ROF is an integration of wireless and fiber optic networks, which provides untethered access to broadband wireless communications in a range of applications including last mile solutions, extension of existing radio coverage and capacity. A Nematic type Liquid Crystal PCF (Photonic Crystal Fiber) is used, which has low loss, light weight, large bandwidth characteristics, and small size and low cable cost which makes it ideal and most flexible solution for efficiently transporting radio signals to remotely located antenna sites in a wireless network. Here we consider a Fractionally Spaced Equalizer (FSE) for electronic compensation of Chromatic Dispersion (CD) and Polarization Mode Dispersion (PMD) in a dually polarized coherent ROF communication system. By analyzing group delay difference and polarization walk off between different frequencies components through proper RF signal processing, both CD and PMD can be precisely determined.