Font Size: a A A

Tunable L-band Erbium-doped Fiber Ring Laser

Posted on:2006-05-17Degree:MasterType:Thesis
Country:ChinaCandidate:L XiaoFull Text:PDF
GTID:2168360155453445Subject:Communication and Information System
Abstract/Summary:PDF Full Text Request
It has been over two decades since the first experiment of fibercommunication was operated in 1978. Fiber-optic communicationtechnologies have been put into commerce step by step. The speed offiber-optic communication has been growing from 45Mbits/s to 40Gbit/s.How to use the exiting communication system to widen the communicationcapability to meet increasingly demands has have become the hotspot ofthe optical communication realm research, when all kinds of data servicesrequire more and more transmission bandwidth. The current WavelengthDivision Multiplexing(WDM) applications and systems mainly useconventional wavelength band(1530-1565nm). As the erbium-doped fiberamplifier(EDFA) is gradually mature,WDM system from C-band toL-band(1570-1610nm) is necessary trend. Meanwhile, L-bandcommunication transmitter has also become research hotspot.Under this background , the author develops a tunable L-bandErbium-doped fiber ring laser instructed by Processor Guo Yubin duringthe postgraduate study. The tunable bandwidth of the fiber laser is from1569nm to 1610nm, covered the whole L-band. Using high density EDFAcan shorten the fiber availably, contracted the structure size consumedly,raise the stability and output characteristic of the light source. Highperformance erbium-doped fiber laser which has bright applied foregroundare acquired by the way of choosing reasonable parameters, such ascoupling ratio of output coupler and optimizing the structure of theresonance cavity. Literature search shows that there are not achievementsand research in this area is in vogue. Consequently, this thesis will unfoldthe study focus on this point, in the expectation of offering the theory andexperiment reference for the methods of L-band fiber laser.Firstly, the thesis introduced the creation principle of the laser and thebasic structure and the work principle of the fiber-optic laser machines.Pump laser, gain medium and optical resonance cavity as three componentsof fiber lasers are analyzed theoretically in details, especially inerbium-doped fiber laser.Secondly, the thesis detailedly introduced the develop process oftunable L-band Erbium-doped fiber ring laser. Pump source chooses980nm semiconductor laser. In order that amplified spontaneous emission(ASE) move to L-band, we adopt high density erbium-doped fiber(11m+1.8m), ring cavity structure and second pump technology. Mostpopular schemes of tunable filter are summarized and compared, such asFabry-Perot interferometer filter, thin file interferometer filter, tunablefiber grating and so on. A feasible wavelength selection mechanism isformed by the combination of a polarization controller and a polarizer isdemonstrated. The theoretical basis is polirization characteristic of the lightand birefraction in single mode fiber. When line polirization lights frompolarimeter transmit in cavity, their polirizaton state will be change.Polirization direction of some line polarization light is not consistent withthe polirization direction of line polorization by adjusting polirizationcontroller. Its loss is least and it is easiest to form laser. By this way,wavelength is tunable. By importing an high birefraction polirization fibercan improve birefraction effort. After transporting one loop, it can makethe polirization direction of different light different greater and loss is most.Therefore, it can reduse the mode compete and compress lineband oflaser .This equipment has four strongpoint, simple structure, low insertionloss , wide tunable range and low cost .Finally, on the basis of theoretical design, the apparatus andcomponents for the experiment were actively prepared and set up.Debugged the experiment and measured the main technological indexes.The main technological indexes of the scheme test and verification...
Keywords/Search Tags:polarization, L-band, high birefraction, fiber ring laser
PDF Full Text Request
Related items