Frequency16-tupled optical millimeter wave generation using dual cascaded MZMs and 2.5 Gbps RoF transmission

Optical Millimeter Wave (MM-Wave) generation with the highest frequency multiplication factor is one of the most promising techniques which can eliminate the need of high frequency local oscillator at the central station. In this paper, a filterless frequency16-tupled optical MM-Wave is generated using dual stage cascaded Lithium Niobate Mach-Zehnder modulators (LN-MZM). By properly adjusting the MZM biasing parameters and phase of the RF signal, eighth order optical sidebands only are generated which can result in 16-tupled millimeter wave at the photo detector. Optical sideband suppression ratio (OSSR) of 61 dB and radio frequency spurious sideband suppression ratio (RFSSR) of 48 dB are achieved in this method. As no filtering is involved in the generation, tunability over entire MM-Wave frequency band can easily be achieved. Impact of various non-ideal parameters such as RF phase, Extinction Ratio(ER), optical input power imbalance between the arms on the optical and RF sidebands is analyzed. The transmission performance of this scheme is evaluated by modulating 2.5 Gbps data and transmitting the same over10 km, 20 km and 25 km Radio over Fiber (RoF) links. Further, the impact of the laser linewidth on the transmission performances is also analysed and presented.