Fiber Grating Sensor System Light Source Research

The erbiun-doped fiber fluorescent source and laser source were studied, and the erbiun-doped fiber source suiting for the fiber Bragg grating(FBG) sensing system was designed. Simultaneously the problem about using the erbiun-doped fiber source (EDFS) in FBG sensing system was studied.Firstly, Based on introducing the erbium-doped fiber fluorescent source(EDFFS) about it's characteristics, basic theory, structure and operating characteristics, analyzed and compared the characteristics of the source's output Spectrum about four basic structure of single-pass forward (SPF), single-pass backward (SPB), double-pass forward (DPF), double-pass backward (DBF), and dual-stage double-pass structure. In different structure ASE(amplified spontaneous emission)l source, primarily studied the influence to the output power, the average wavelength, spectral flatness and power stability, which caused by that parameters of the different fiber length, pump power, fiber loop reflector. And studied the function in improve the output spectrum by designing different structure. In experiment, adopted the single-stage double-pass backward structure and the dual-stage double-pass backward structure to produce C-band ASE source and C+L-band ASE source. The EDFSS had been used in FBG sensing system. There's a C-band spectrum with the typical power of 30.8mW, 3dB bandwidth was 33.48nm, center wavelength was 1545.00nm, the flatness was less than 2dB. The C+L-band with the typical power of 33.5mW, 3dB bandwidth is 75.0nm, center wavelength was 1563.76nm, the flatness was less than 2dB. After working more than 72 hours, its performance come up to the light design requirements, the output power stability was better than 0.5dBm. It can better meet the applications of distributed FBG sensing, passive device testing or some occasions.Secondly, based on studing the working principle and structure of the erbium-doped fiber laser(EDFL), the output spectrum characteristics of the erbium-doped fiber ring laser(EDFRL) was studied, and the characteristic parameters of EDFRL were optimized. Finally achieved the output spectrum with power of 10.2mW, the peak wavelength was 1552.625nm, the 3dB bandwidth was 0.0472nm, the sidemode suppression ratio(SMSR) was 54.47dBm. realized tuning the output wavelength of fiber laser through tuning the wavelength of FBG with temperature. In 20℃-170℃temperature range we realized the laser outputs that wavelength was from 1547.7nm to 1556.5nm. It's tuning linearity reaches as high as 99.96%, The spectrum 3dB bandwidth was smaller than 0.05nm, 20dB bandwidth was smaller than 0.08nm, the SMSR was bigger than 50dBm, The power stability surpassed 0.2dBm。Simultaneously based on undertaking research item, introduced the application characteristics of EDFFS and EDFLS, the existing problem and the solution technical method in the FBG sensing examination system. A novel detecting technology with lasing wavelength was presented, which's based on tunable EDFL technology. In temperature and strain examination, the anticipated system resolving power could reach 0.1℃and 1με, which suitable for the distributional FBG sensing examination system.Finally, the shortages of the study were analyzed, which definitized the target and the problem to be solved in the future study.