Study On The Generation And Application Of Microwave Signals Based On Fiber Laser

Microwave technology is widely used in the fields of high-speed broadband wireless access,radar and satellite communication,electronic warfare,sensor network and astronomical detection.The generation and procession of high frequency microwave signals have become a hot spot of research.Microwave photonics is a new interdisciplinary subject to this development demand,which processes microwave signals with optical method.Compared with the traditional microwave technology,microwave photonics technology has significant advantages,including low loss,anti electromagnetic interference,wide bandwidth and so on.It can solve the difficult problems that traditional microwave technology can hardly settle.Therefore,it is of great significance to use optical methods to deal with microwave signals.The generation and application of microwave signals based on fiber laser have been researched in this paper.This paper has introduced the research state of multi-wavelength Brillouin fiber laser,mode-locked fiber laser,the generation of high-frequency microwave signal,fiber laser beat frequency temperature sensing technology and the hybrid transmission of laser signal and microwave signal.The microwave signals generation based on multi-wavelength brillouin fiber laser and mode-locked fiber laser are analyzed from theoretical aspects,respectively.The multi-wavelength brillouin fiber laser based on stimulated Brillouin scattering effect,the generation of high-frequency microwave signals based on dual-wavelength Brillouin fiber laser and the generation of high-frequency microwave signals based on mode-locked fiber laser areresearched,respectively.The high sensitivity temperature sensing system based on beat frequency microwave signals and the hybrid transmission system of laser signal and microwave signal based on beat frequency modulation technology are built up from the above research.The main research contents and academic contributions of this paper are as follows:1.Multi-wavelength Brillouin fiber lasers based on stimulated Brillouin scattering effect have been researched.Multi-wavelength lasers with single Brillouin frequency shift spacing,double Brillouin frequency shift spacing and triple Brillouin frequency spacing shift have been achieved through designing different structures.The influences of the pump power,the wavelength of pump and the power of erbium-doped fiber amplifier on multi-wavelength laser signals output are analyzed,respectively.2.The generation of high-frequency microwave signals based on dual-wavelength Brillouin fiber lasers has been researched.The~10,20,30 and 40 GHz high-frequency microwave signals can be obtained by beat frequency detection of the dual-wavelength laser signal with different Brillouin frequency shifts.The single longitudinal mode dual-wavelength laser signal can be achieved by changing the length of the gain medium,adding the double-ring structure and the Sagnac loop filter structure.The ultra-narrow linewidth high-frequency microwave signals can be obtained.3.The generation of high-frequency microwave signals based on mode-locked fiber laser has been researched.The 406.8 MHz high-frequency microwave signal sequence can be obtained by using the passive mode-locked fiber laser based on nonlinear polarization rotation effect.The mixed mode-locked fiber laser based on nonlinear polarization rotation effect and semiconductor saturable absorption mirror is designed in order to increase the non-linear effects of the cavity to generate high-frequency microwave signal sequence with higher frequency spacing.Accordingly,1.78 GHz high-frequency microwave signal sequence is obtained.4.High sensitivity temperature sensing system based on beat frequency microwave signals is designed.The temperature information can be measured by filtering and beat frequency detection of multi-wavelength laser signals,which are generated by the sensing multi-wavelength Brillouin fiber laser and the reference multi-wavelength Brillouin fiber laser.The temperature sensitivity of 2,4,6,8 and 10 order Stokes signals is 2.111 MHz?°C?4.688 MHz?°C?6.381 MHz?°C?8.516 MHz?°C and 10.732 MHz?°C,respectively.5.The hybrid transmission system of laser signal and microwave signal based on beat frequency modulation technology is constructed.The hybrid transmission of laser signal and microwave signal can be achieved in the same structure simultaneously,where 10 GHz sinusoidal analog signal and 10 Gbps pseudo-random digital signal can be transmitted while 1550 nm laser signal is used as the carriers.800 MHz sinusoidal analog signal and 300 Mbps pseudorandom digital signal can be transmitted when 10.86 GHz high frequency microwave signal is used as the carriers.The research work in this paper will provide some reference for the applications of fiber laser in the field of microwave photonics.