Optical Generation Of Tunable Millimeter-wave Based On Dual-beam Optically Injected VCSELs

The Radio-over-Fiber (RoF) is a communication technology that uses optical fiber link to transmit radio signal, it can effectively use the characteristics of optical fiber link, such as low loss, high bandwidth, and electromagnetic interference resistance. With the aid of fiber link, the radio signal can be assigned from central station to other base stations, and then the collected radio signal at base stations is transported to central station. As one of the key technologies for supporting the RoF, the generation of optical millimeter wave is particularly important. Currently, there are a variety of methods for generating optical millimeter wave, mainly including optical heterodyning, external modulation, dual-mode semiconductor laser, combining direct modulation and filtering techniques, and period-one state (PI) oscillation in optically injected semiconductor laser. Recently, a method based on dual-beam optically injected distribution-feedback semiconductor lasers (DFB-SLs) to generate optical millimeter wave has been proposed, and it is highly concerned by related researchers.In this paper, a scheme for generating tunable millimeter-wave based on the injection locking state in dual-beam optically injected1550nm vertical-cavity surface-emitting lasers (VCSELs) is proposed, and the nonlinear dynamics of the dual-beam optically injected1550nm vertical-cavity surface-emitting lasers (VCSELs) and the performances of the obtained millimeter-wave have been investigated theoretically. The results show that a slave VCSEL (S-VCSEL) oscillated at1550nm subject to dual-beam injection from two master VCSELs (M-VCSELs) can be driven to enter into injection locking state under suitable injection parameters. Under this case, the outputs of both X and Y linear polarization modes of the S-VCSEL exhibit periodic oscillation whose frequencies are equal to the frequency detuning between the two M-VCSELs, and their optical spectrum contain only two main frequency components and possess a single sideband (SSB) spectrum structure. As a result, two mutually orthogonal optical millimeter-waves can be obtained simultaneously based on the periodic oscillation in the dual-beam optically injected locking S-VCSEL. Through adjusting the frequency detuning between two M-VCSELs, the frequency of the millimeter-wave can be tuned continuously within a large range, while the power and modulation depth can also be controlled by adjusting the system parameters.