Luis Vallejo, a PhD student from Instituto de Telecomunicaciones y Aplicaciones Multimedia, Universitat Politècnica de València (Spain), made his second stay in Czech Technical University in Prague (Czech Republic) from January until March 2021, under the supervision of Stanislav Zvanovec. During his STSM he worked on experimental implementation of full-duplex microwave photonics-based mmW signal generation and distribution in C-RAN, and experimental optimization of capacity in hybrid optical/RF 5G links in the sub-6 GHz and mmW bands using low-cost DML. Furthermore, current and future collaboration between the two research groups have been consolidated.