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Study On Multi-wavelength Erbium Doped Fiber Lasers And Rare Earth Doped Fiber

Posted on:2015-02-09Degree:DoctorType:Dissertation
Country:ChinaCandidate:C F ZhangFull Text:PDF
GTID:1268330425489202Subject:Communication and Information System
Abstract/Summary:PDF Full Text Request
Multi-wavelength fiber lasers are of great interest in recent years for their potential applications in optical communications, optical signal processing and microwave photonics. On the basis of the development of rare-earth doped fiber, optical fiber laser and optical fiber amplifier have made great strides, which made the rare-earth doped fiber with high gain coefficient have always been a hotspot. This dissertation is mainly devoted to the research on stable multi-wavelength erbium doped fiber lasers and fabrication of novel rare-earth doped fiber. Some stable multi-wavelength fiber lasers utilizing polarization hole burning are proposed and demonstrated. A novel erbium doped fiber with high gain coefficient and a photosensitive thulium doped double clad silica fiber with high gain coefficient are fabricated. The major achievements of this dissertation are summarized as follows:1. A stable multi-wavelength fiber laser based on a polarization-maintaining erbium doped fiber is proposed and demonstrated. In the proposal laser, the wavelength competition caused by homogeneous gain broadening of erbium doped fiber is suppressed by utilizing polarization hole burning. Compared with other methods to suppress the homogeneous gain broadening, the proposal laser is easy to realize. Compared with the multi-wavelength lasers using polarization-maintaining fiber Bragg grating to exploit polarization hole burning, the proposal laser can select proper filter to realize the wavelength switch and tuning. Stable single-, double-, triple-, and four-wavelength oscillations are experimentally demonstrated at room temperature. The fluctuation of wavelength and peak power is less than0.05nm and0.5dB over32minutes. The3dB bandwidth and the30dB bandwidth are measured to be less than0.01nm and0.11nm.2. A simple multi-wavelength fiber laser adopting principle of the three-loop polarization controller is proposed and demonstrated. The proposed laser with simple structure is easy to realize. Compared with the multi-wavelength lasers using polarization-maintaining erbium doped fiber to exploit polarization hole burning, the proposed laser realized multi-wavelength lasing operation with low pump threshold. Three-wavelength and tunable dual-wavelength lasing oscillations have been achieved at room temperature. The fluctuation of wavelength and peak power is measured to be less than0.05nm and0.75dB over32minutes. The3dB bandwidth of each lasing oscillation is0.01nm and the30dB bandwidth is0.1Onm.3. The gain coefficient of the erbium doped fiber is theoretically studied through the model of Giles. Higher gain coefficient can be achieved by increasing the overlapping factor of the erbium doped fiber. In the process of fabricating fiber preform, two soot layers for solution doping are deposited. The refractive index of the first soot layer is equal to that of the fiber cladding due to fluorine doped. As a results, the doped region is larger than fiber core and the overlapping factor is increasing. This method is able to make the erbium doped fiber with high concentration achieve more higher gain coefficient.4. Photosensitive thulium doped double clad silica fiber with high gain coefficient was manufactured by MCVD process and solution doping technique. The effective absorption coefficient at800nm,1210nm and1600nm are1.27dB/m,2.11dB/m and2.68dB/m respectively. Utilizing the fiber in a laser, a lasing output of2.10W at1946.9893nm can be obtained.
Keywords/Search Tags:Multi-wavelength fiber laser, Polarization hole burning, Polarizationmaintaining fiber, Polarization controller, Erbium doped fiber, Thulium doped fiber
PDF Full Text Request
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