Research On Dual-wavelength Fiber Laser Based On SOA And Its Applications

The dual-wavelength fiber laser has many outstanding advantages such as good stability,high conversion efficiency,and low cost.It has been widely used in optical communication systems,fiber sensor networks,spectroscopy,and optical information processing.Semiconductor optical amplifier?SOA?has the advantages of wide wavelength range,compact structure and easy integration with other optical components.Dual-wavelength fiber laser based on SOA has gradually become the focus of research.In this dissertation,the theory of microwave signal generated by optical heterodyne method is analyzed firstly,then the dual-wavelength fiber laser based on SOA with LD-injected,the dual-wavelength fiber laser based on SOA with semiconductor saturable absorption mirror?SESAM?,the dual-wavelength fiber grating laser based on SOA and their application in photo-generated microwave signal are studied.The main research contents include:1. Theoretical study on the generation of microwave signal by the optical heterodyne method.The principle of generating the microwave signal by the optical heterodyne method is to beat the two lasing signals with a certain frequency difference at the photodetector.Through detailed theoretical derivation,it can be seen that the two lasing signals with the frequency f₁and f₂respectively pass through the photodetector,and the microwave signal with frequency f₁-f₂can be obtained after photoelectric conversion.2. A tunable dual-wavelength fiber ring cavity laser based on SOA with LD-injected is proposed and experimentally studied.Two externally injected distributed feedback?DFB?lasers were used as the wavelength selector,and the output wavelengths of the dual-wavelength fiber laser are locked and tuned by the two injected DFB lasers.The experimental results show that when one DFB laser operates at 25?and the other DFB laser operates at 0?,stable dual-wavelength lasing oscillation can be achieved at 1553.68 nm and 1553.9 nm with a wavelength spacing of 0.22 nm.The wavelength spacing can be tuned by adjusting the operating temperatures of the two injected DFB lasers.When the temperature difference of the two DFB lasers varies from25?to 0?,dual-wavelength lasing whose wavelength spacing can be tuned within the range of 0.22 nm to 2.95 nm is obtained.3. A dual-wavelength ring cavity continuous wave fiber laser based on SOA with SESAM is proposed and experimentally studied.Using SOA as the gain medium and the energy supply source of the dual-wavelength fiber laser,SESAM realizes the selection and loss modulation of the oscillation modes in the laser cavity.Studies have shown that when the input current of SOA is 140 m A,by carefully adjusting the polarization controller?PC?,dual-wavelength lasing output of 1560.91 nm and 1564.12nm can be obtained with a signal-to-noise ratio of greater 30 d B and a wavelength spacing of 3.21 nm.4. A dual-wavelength fiber grating laser based on SOA is proposed and experimentally studied.A pair of uniform fiber Bragg gratings?FBGs?are used as the wavelength selection elements of laser cavity.The output wavelengths of the dual-wavelength fiber grating laser are locked by the Bragg wavelengths of the two FBGs.The results show that when the operating temperature of FBG1 is 25?and the operating temperature of FBG2 is-10?,stable dual-wavelength continuous-wave lasing output with center wavelengths of 1549.58 nm and 1548.98 nm can be obtained by carefully adjusting the PC.The wavelength spacing is 0.6 nm.By changing the operating temperature of FBG2 to change the temperature difference between the two FBGs from 0?to 35?,dual-wavelength continuous wave lasing with a wavelength spacing from 0 nm to 0.6 nm can be realized.5. Research on microwave signal generation of dual-wavelength fiber grating laser based on SOA.When the input current of SOA is 120 m A,the operating temperature of FBG1 is 25?,and the operating temperature of FBG2 is-10?,stable dual-wavelength lasing output is realized at 1549.58 nm and 1548.98 nm,and the wavelength spacing is 0.6 nm,corresponding to the microwave signal of 74.9 GHz.The principle verification of the microwave signal generated by the optical heterodyne method is performed on the Optisystem software.When the operating temperature difference between the two FBGs varies from 10?to 35?,the wavelength spacing can be tuned from 0.18 nm to 0.6 nm,and the corresponding microwave signal frequency is22.5 GHz to 74.9 GHz.