An Improved Radio Over Fiber System With High Sensitivity and Reduced Power Degradation by Employing a Triangular CFBG

We propose and demonstrate a prototype for an improved intensity modulation direct detection (IMDD)-based radio over fiber (RoF) system by employing a homemade triangular chirped fiber Bragg grating (CFBG). In the scheme, an intensity modulator first modulates the lightwave with millimeter-wave driving signals to realize optical double-sideband (DSB) modulation, and then the output DSB signals pass though a triangular CFBG. Because the triangular CFBG is with a negative slop in spectrum, the lower sideband experiences higher attenuation than the upper sideband, which means the optical single sideband with carrier (OSSB+C) modulation can be easily implemented. The process of triangular CFBG also improves the link performance by balancing optical carrier-to-sideband ratio. As our scheme only uses a commercially used intensity modulator and homemade triangular CFBGs, the system is guaranteed with cost-effective architecture and good performance.