Multiwavelength Brillouin Erbium-Doped Fiber Laser With Wavelength Spacing Of Multiple Brillouin Shifts

With the increasing demand for information capacity,the high-speed,large-capacity and longdistance telecommunication is the development trend for the next generation of all-optical network.In order to make good uses of the limited resource of communication frequency,Dense Wavelength Division Multiplexing(DWDM)with frequency spacing of 10 GHz,20GHz or 30 GHz will be an important development direction for future technology.Combining the nonlinear gain of stimulated Brillouin scattering in the fiber with the linear gain of the erbium-doped fiber,is an effective way to generate a large number of multiple wavelengths.Multi-wavelength fiber lasers have wide applications in many fields,including DWDM optical fiber communication systems,microwave signal generation,optical instrument testing,optical fiber sensing and spectrometry.In this dissertation,the main research contents are as follows:Firstly,the multiwavelength Brillouin erbium-doped fiber lasers with double and triple Brillouin frequency shifts was firstly studied.8 Brillouin-wavelength laser generation with double-wavelength Brillouin frequency shift of 0.17 nm has been obtained,with output wavelength tuned in 110 nm range(1528 nm to 1638 nm).5 Brillouin multiwavelength laser with a wavelength spacing of three time Brillouin frequency shifts of 0.26 nm were also obtained,the output wavelength can be tuned within 60 nm(1535 nm to 1595 nm).It has been found that Brillouin pump laser wavelength is in the laser self-oscillation wavelength range,the maximum number of Brillouin wavelengths can be generated.Secondly,a novel random tunable multiwavelength fiber laser based on Brillouin scattering has been proposed and demonstrated with half-open cavity,which is formed with a 3dB coupler as total reflection for one end and randomly distributed Rayleigh scattering in the single mode fiber for the other end.When the pump power is high enough,it is possible to generated high-order stimulated Brillouin scattering in the SMF and achieve multi-wavelength output.Seven Stokes wavelengths have been experimentally obtained.The wavelength can be tuned in the range of 50 nm(1515 nm-1565 nm).