Study Of Ultrahigh Resolution Optical Spectrum Analyzer By SBS In Optical Fibers

The ultrahigh resolution Optical Spectrum Analyzer (OSA) based onstimulated Brillouin scattering (SBS) in single mode fibers is studied in this paper.The thesis has three sections: Firstly, the basic theory and related characteristic ofSBS is studied; Secondly, we research the analytical and numerical solutions of SBSwith LabVIEW program; finally, the software and hardware constructions ofBrillouin Optical Spectrum Analyzer (BOSA) is developed and the measurementresults of BOSA is provided. In additions, we also use the theory of Time-FrequencyAnalysis (TFA) to check the sweeping speed of Tunable Laser Source (TLS), andtest this method. The detailed contents are listed as the following:1. The optical scatterings in medium, specially the Brillouin scattering in opticalfibers, is firstly introduced. and how the SBS is excited are discussed in detail.The SBS threshold, the polarization status of the two int eraction light beamsand Brillouin gain spectrum bandwidth, and the influence of thesespecifications for our BOSA system are discussed from theory andexperiments. We also introduce the main applications of SBS in fibers. Thebasic principle of BOSA is introduced.2. The basic of Virtual Instruments (VI) is introduced. Then the calculation ofSBS is studied, with popular graphical programming language LabVIEWfrom NI Company. The simulation results of SBS are presented with specialparameters. Time-frequency analysis used in BOSA system is applied.3. The hardware devices used in BOSA system are listed, and the constructsof light and electrical paths is presented in details. And we introduce thebasic contents, such as Case Structure, TDMS file style, then the detailsoftware program is presented. At last, the experiment results of TFA areprovided. 4. Finally, we introduce the performance of ORION laser module and fiberDFB laser used as SUT light, and measure their spectrum with AQ6370COSA. Then test the SBS spectrum of it with BOSA constructed by us, andresearch the results of test. We also present the resolution and weak lightpower measurement of BOSA system.