Photonic generation of 32-tupling millimeter-wave signal employing cascaded dual-parallel Mach-Zehnder modulators optimized by differential evolution for advanced optical communications

Abstract Optical millimeter-wave (MMW) generation is one of the key technologies of advanced optical communications systems of the next generation, such as 6G. Photonic based MMW generation with optical frequency multiplication has a number of advantages, which include low loss, wide tunability and easy integration with fiber-optics networks. Nevertheless, this is difficult to realize high multiplication factors with a high output power and harmonic purity. We present a 32-tupling optical MMW generation system based on cascaded dual-parallel Mach-Zehnder modulators (DPMZMs) that are optimized with the help of differential evolution (DE). DE algorithm uses five parameters including RF amplitude (VRF), phase shifts (φ 1 , φ 2 ), optical gain and electrical gain to maximize the 32× harmonic power at 160 GHz. It has a 5 GHz RF input and a 160 GHz MMW output with 0 dBm output that is 15.8 dB higher than the baseline with a signal-to-noise ratio of 70 dB. The optimized values are V RF = 23.09 V, φ 1 = 44.7deg, φ 2 = 97.4deg (of the DPMZMs), optical gain = 43.0 dB and electrical gain = 26.0 dB. It produces 12 usable harmonics between 10 GHz and 240 GHz. DE-optimised architecture provides a photonic MMW generation based on filterless solution with high performance.