“…Besides the low production cost, VCSELs also offer desirable characteristics, for instance, low threshold current, circular output-beam profile, single-longitudinal mode operation, wafer-scale integrability and longevity. A widely continuously tunable photonic microwave generation based on P1 in an optical injection VCSEL has been demonstrated recently [11]. In [11], two local maximum microwave powers at the two detuning frequencies at a fixed injection power for the higher injection power region have been observed, which has not been shown in DFB lasers and QD lasers.…”