Improving Dynamic Range of RoF System Using Dual-Drive Mach-Zehnder Modulator
A novel radio over fiber (RoF) system incorporating a dual-electrode dual-parallel Mach-Zehnder modulator (DE-DPMZM) is used to transmit vector signal to minimize the distortions that are caused by the Mach-Zehnder modulator (MZM) nonlinearity. The MZMs are biased such that the offset voltage in both the MZMs is opposite. A 30 MSym/s 16-QAM signal is transmitted after single-sideband modulation, and the detected signal is analyzed for its error vector magnitude (EVM) performance. The measured EVM is 8.363% which shows there is much improvement in the EVM performance. The system is cost-effective since it rectifies the nonlinearities of the Mach-Zehnder modulator using the simplest optical methods and the EVM% shows that proposed biasing results in higher dynamic range.
KeywordsRoF Dynamic range Nonlinearity