All-optical flexible 5G signals generation and transmission for spectrum resources optimization

As available spectrum gets congested by different applications, spectral efficiency can be enhanced through spectrum sharing and coexistence. In this paper, we demonstrate the idea of spectrum sharing and coexistence by using optical heterodyning as a flex-spectrum photonic RF transmitter. Flexibility was achieved by tuning the RF carrier frequency from 1–5 GHz, frequencies around two spectra from a commercial telecom antenna and from a radio astronomy observatory area. We compared the spectrum of our adopted flex-spectrum photonic RF transmitter with these two practical spectra. This allowed us to demonstrate the feasibility of our adopted photonic RF transmitter to coexist with these distinct spectra. Results indicated that it is feasible to use these adopted photonic transmitters in different application environments for coexistence and spectrum sharing. Error-free 26 km fiber transmission was achieved at 2.1 Gbps and 8.5 Gbps. This further showed the feasibility of these photonic RF transmitters for controlled transfer of different data signals relating to different applications using the same RF channel.