The separation for simultaneous transmission of baseband and microwave signals in a radio-over-fiber system

Abstract

Simultaneous generation and transmission of 10-Gb/s baseband signal and 20-GHz microwave signal with 155-Mb/s on-off-keying (OOK) data on a single wavelength over 50-km-long fiber link based on a dual-parallel Mach-Zehnder modulator (DPMZM) are investigated. After simultaneous modulation of the baseband signal and microwave signal at central office (CO), the hybrid signals are separated by interleaver(IL) or fiber Bragg grating (FBG) at base station (BS). The center wavelength spacing and bandwidth of IL, also the reflection ratio, center wavelength and bandwidth of FBG are to be considered carefully as the baseband and microwave signal are only tens of GHz spacing and hard to be separated with each other. Through theoretical analyses and simulation, for the demonstrated hybrid transmission system, the relations of Q factor with the reflection ratio and bandwidth of FBG are analyzed separately in different fiber links (SMF and DSF).