Abstract
A filterless radio-over-fiber system to generate 40 and 80 GHz millimeter-wave was proposed by using two Mach-Zehnder modulators (MZMs). The two MZMs are biased at the maximum transmission point to suppress odd-order sidebands. By adjusting the modulation index of the two MZMs and the radio frequency drive signals, only the two 2nd and 4th order sidebands are retained. Subsequently, by adjusting the polarization direction to generate 40 and 80GHz frequency millimeter-wave signal. Detailed theoretical analyses and simulations are provided. The simulation results show that the 40 GHz millimeter-wave signal was obtained with 30 dB optical sideband suppression ratio (OSSR) and the 80 GHz millimeter-wave signal was obtained with 25 dB OSSR. Thanks to the higher OSSR, the generated MMW signal is not greatly affected by power fluctuations during transmission or frequency tuning. Furthermore, the effects of the modulation index, bias voltage and extinction ratios deviate from the ideal value on millimeter-wave performance are also analyzed and verified, showing the proposed scheme is relatively flexible from the limitation of filter fixed bandwidth and economical.
Highlights
Radio over Fiber (RoF) technology is an emerging communication technology that combines optical fiber communication and untrusted communication [1]
In an RoF system that generates millimeter waves based on external modulation, the optical signal is generally only used as a transmission carrier, and the RF signal is modulated onto the carrier in different ways
The RF driving signals are 10 GHz, which is generated by the signal generator and the phase difference is π between the upper and lower arms of Mach–Zehnder modulators (MZMs).The modulation index of MZM1 is equal to 2.40.The modulation index of MZM2 can be set to 0.2
Summary
Radio over Fiber (RoF) technology is an emerging communication technology that combines optical fiber communication and untrusted communication [1]. Zhu et al proposed a new scheme to obtain a higher frequency millimeter-wave by using two dual-parallel Mach–Zehnder modulators (DP-MZMs) [22]. They proposed a high spectral purity microwave signal generation scheme based on series connected PolMs [26]. They used DPPolM in both systems, which provided new ideas for our subsequent research. By controlling the angle between the main axis of one of the polarizers and that of the polarizing beam combiner (PBC), the OSSR of the generated optical carrier can be flexibly controlled, so that the multiplication factor of the system can be adjusted.In compared to the above-described technologies, our system demonstrates higher flexibility, adjustability and reduced signal power fluctuation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
