| 1.7?m light source has great application prospects in biomedical and infrared light sources.In recent years,the research on the gain spectrum of 1.7?m light source is a hot topic in international research,while domestic research is still in the early stage.The 1.7?m high-performance light source and related applications have yet to be further studied and developed.In this paper,we use erbium-doped fiber and fiber nonlinear effects to study 1.7?m broadband light source.First,the related theory,generation and optimization methods of broadband gain spectrum in 1.7?m band are studied.The gain spectrum generated by the non-linear effects of Erbium-doped fiber and fiber was experimentally studied,and the desired broadband light source is obtained through optimization.Finally,a time-domain optical coherence tomography system(TDOCT)was built,and preliminary imaging results are obtained,laying the foundation for verifying the advantages of the 1.7?m broadband light source in optical coherence tomography.The main research content is summarized as follows:1.The generation method and related theory of 1.7?m broadband light source is analyzed and summarized.Including the energy level structure and spectral characteristics of Tm3+ ions,the long-band absorption characteristics of dispersion-compensating fibers and photonic crystal fibers are also studied.In addition,the theories of stimulated Brillouin scattering,stimulated Raman scattering,and modulation instability are analyzed.From the principle of nonlinear effects,a method of generating a broadband light source in the 1.7 ?m band is analyzed.2.Based on the theoretical analysis results,a 1.7?m gain spectrum experimental system using erbium-doped fiber and dispersion-compensating fiber as gain medium is built.The ytterbium-doped fiber pumped by a 1565 nm laser source produced a spectrum in the 1750-2200 nm range.The dispersion shifted fiber was then connected to different lengths to study the variation of the gain spectrum.After optimization of the pump power,erbium-doped fiber and dispersion-shifted fiber length,a broadband light source with a center wavelength of 1744 nm,a peak power of-44 dBm,and a 5 dB spectrum width of 87 nm is obtained.3.The regularity of non-linearity effects of amplified spontaneous emission(ASE)light sources and multi-mode continuous light sources in different dispersion regions of optical fibers is studied.According to the regularity,an experimental system with ASE light source and multi-mode continuous light as the medium of pump,dispersion displacement and high non-linear optical fiber is constructed.In the experiment,the dispersion-shifted high-polarization fiber is pumped using a 1.55?m band filter ASE light source,and the gain spectrum of different dispersion regions is studied.The erbium-doped fiber is used to absorb the excess pump light to correct the gain spectrum,thereby obtaining a broadband light source with a center wavelength of 1674 nm,a peak power of-27 dBm,a 10 dB spectral width,and a wavelength of 100 nm.Secondly,on the basis of the aforementioned experiments,multi-mode continuous optically pumped dispersion-shifted high-polarity optical fibers are further used.By optimizing the fiber length and pump power,a broadband light source with a peak wavelength of 1668 nm,a peak power of-24 dBm,and a 10 dB spectral width of about 25 nm is obtained.4.A time-domain optical coherence tomography system based on fiber optics is built to optimize the parameters of the system and to achieve tomographic imaging of the plane mirror.This lays the foundation for verifying the advantages of the 1.7?m broadband light source in optical coherence tomography. |
PDF Full Text Request