Research On C+L Band High Flatness Broadband ASE Light Source

C+L band(1530nm-1625nm)broadband ASE light source is a new type of broadband light source,which has wide spectral width,high output power,stable wavelength,easy to fiber coupling,long life and other characteristics.It is a kind of wideband light source that can generate broadband light by using erbium-doped amplified spontaneous emission(ASE).The application of C+L band broadband ASE light source to fiber optic communication component test,fiber sensors and fiber optic gyroscope is very important.Therefore,the broadband ASE light source draws more and more attention in recent years.At present,the flatness of broadband light sources in the market is mostly concentrated above 3dB,which is not only not conducive to multi-point measurement and accurate demodulation of distributed FBG sensing system,but also reduces the available bandwidth and causes serious error rate in communication applications.This thesis aims at the research on high-flatness broadband light output of C+L band broadband ASE light source,the basic principle of C+L band broadband ASE light source is analyzed,and the C+L band broadband ASE bases on a configuration named double-pass bidirectional,which has the advantages of high pumping efficiency,good stability and large output power.The influences of erbium-doped fiber length,pump power,pump wavelength and broadband reflector on the output spectrum of wideband light source are analyzed by Optisystem software.The analysis of the output spectrum from C-band to L-Band to the formation of C+L band,and find a way to improve the flatness of broadband ASE light source.The whole hardware platform including voltage regulator circuit,laser driver circuit,and temperature control circuit and so on is designed and researched.Among them,the laser driver circuit can achieve stable and adjustable current output,the laser output power error control within ± 0.1%,and the laser from abnormal damage.At the end of the thesis,the whole C+L band broadband ASE light source is experimentally tested,and the optimal output spectrum is obtained.Without adding anyGFF,the spectrum is from 1525 nm to 1600nm(75nm),the flatness is 2dB,the output power of 15.58 mW.This broadband ASE light source can be applied to high flatness requirements of high-precision FOG,distributed fiber grating sensing and other fields.