Photonic Microwave Generation Based On Period-one Nonlinear Dynamics Of An Optically Injected Semiconductor Laser

The Ro F communication system combining wireless communication and optical fiber communication technology utilizes high-speed,large-capacity,low-loss optical fiber communication to provide communication bandwidth for the traditional wireless communication,which increases the communication capacity and the transmission distance,and at the same time overcomes the wireless Communication transmission loss,serious interference and other issues,therefore,can better meet people’s demand for communication bandwidth and speed.Photonic microwave technology,one of the key technologies supporting the Ro F communication system,utilizes a photonics method to generate microwave signals.Because of its advantages of high frequency,ability to transmit in optical fibers,immunity to electromagnetic interference,and easy wavelength division multiplexing,it has received widespread attention and research in recent years.Therefore,the research of it has important value and has gradually become a research hotspot in recent years.The common optical microwave technologies mainly include optical heterodyne,direct modulation,external modulation,photoelectric oscillator methods,and period-one(P1)oscillation based on optically injected semiconductor lasers(LD).Among them,the method of generating microwave by P1 based on optically injected LD is favored by people due to its advantages of high-frequency,single-sideband spectral structure characteristics,continuous adjustment of the frequency range,and the like.In this paper,a widely tunable narrow-linewidth photonic microwave generation scheme based on the period-one dynamics of an optically injected distributed feedback semiconductor laser(DFB-LD)combined with optoelectronic loops is proposed and experimentally demonstrated.The advantage of this solution is that it combines the Widely tunable features of period-one(P1)oscillation based on optically injected DFB with the narrow linewidth characteristics of the optoelectronic circuit,and solves the contradiction between the single-mode output and the high-Q value by introducing a dual-loop optoelectronic loop.The results show that the optical injection first drives the laser into P1 dynamics so that its intensity oscillates at a microwave frequency,which can be widely and continuously tuned in the range from 8 GHz to 67 GHz.Under appropriate implantation parameters,a photonic microwave signal with a single-sideband structure characteristic of the spectral structure can be obtained.By using optoelectronic loops,the linewidth of the photonic microwave is effectively reduced from 8.6 MHz to 30 k Hz and a signal to noise ratio above 40 d B is obtained.