Sub-60-GHz power-efficient fronthaul system of up to 16-Gbps using RF carriers generated from a gain-switched VCSEL

Future fronthaul wireless networks will be more competitive and attractive if they can use power- and cost-efficient transmitter systems to realize both extended reach and enhanced network capacity. Photonic generation of high-frequency RF carrier signals is currently considered an attractive technique. The laser gain-switching technique for photonic generation of high-frequency RF carrier signals has attracted great interest recently and is a cost-efficient scheme. Vertical cavity surface emitting laser (VCSEL) are power-efficient optical sources requiring bias currents below 10-mA. The use of VCSELs for gain-switched optical frequency comb generation has proven to be attractive in the term of power-efficiency. However, the data transmission performance of these gain-switched VCSEL optical frequency combs are yet to be demonstrated. In this paper, for the first time to our knowledge, we numerically demonstrated that RF carrier signals generated from a gain-switched VCSEL optical frequency comb can support up to16-Gbps error-free data transmission over fiber length beyond 20-km. A 56-GHz RF carrier signal was amplitude-modulated with 10- and 16.3-Gbps data before error-free transmission over 20.5-km of standard single mode fibers. Transmission penalties of 2- and 7-dB were recorded at 10- and 16.3-Gbps, respectively, at receiver sensitivities below -17-dBm.