Dissertation > Industrial Technology > Radio electronics, telecommunications technology > Photonics technology,laser technology > Laser technology, the maser > Laser

The Study of Multi-wavelength and Narrow-line-width Fiber Laser Based on Polarization Effects

Author DongFengJuan
Tutor YangXiuFeng
School Tianjin University of Technology
Course Communication and Information System
Keywords Laser Technology Birefringence effect Multi - wavelength fiber lasers Narrow linewidth Polarization rotation Polarization hole burning
Type Master's thesis
Year 2011
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With the increasing development of modern fiber-optic WDM communication systems, to further improve the communication capacity to be needed to solve the problem. The most effective way is to increase the number of channels, and provide multiple signal the most direct way is to use multiple single-wavelength lasers. However, simply using a plurality of single-wavelength laser will increase the cost and complexity of the system, therefore, it is possible to also provide a multi-wavelength laser source of the plurality of channels competing research hotspot. Multi-wavelength and narrow linewidth fiber laser ring cavity based on the the fiber polarization of the birefringence effect as the research object, a series of theoretical and experimental research related. The main content of this paper include: 1. Expounded the basic types of multi-wavelength fiber laser and its related principles. 2. Proposed a scheme based on nonlinear polarization rotation effect tunable multi-wavelength fiber laser experiments and experimental studies. Transmission function T and wavelength λ and the relationship of the power P analysis and research; come to the differences in the the output wavelength characteristics of the different output coupling ratios, the experimental results show that: the output coupler output coupling is greater the larger the output power uniformity as possible, but the output decrease in the number of wavelengths. And the reasons are the analysis and research; obtained in the case the output coupling ratio of 10%, the wavelength interval of 0.35nm, a stable output of the output power of about-7dBm up to 17 wavelengths. 3. Proposed an experimental program beat effect dual-wavelength fiber laser based on multimode fiber and experimental research. Theoretical analysis and experimental study of the introduction of multi-mode fiber space mode beat effect; multimode fiber mode beat effect can be used to suppress the the uniform gain erbium-doped fiber multi-wavelength output and the wavelength interval with the the length of the multimode optical fiber varies: the multi-mode fiber is the longer, the smaller the wavelength interval. Due to polarization hole burning and polarization-dependent and polarization controller on the cavity of the control and adjustment of the polarization state, to obtain the output power of about-2dBm, extinction ratio of greater than 43dB dual wavelength output. 4 proposed a dual-wavelength fiber laser based on polarization rotation and a high finesse filter narrow linewidth. Theoretical analysis and simulation output function of the high-finesse filter characteristics; were given before and after a high-finesse filter output spectrogram. And analysis of the changes in the laser output before and after joining the finesse filter and reason; experimental results show that: adding finesse, has been the line width of 0.16nm, extinction ratio of 18dB side mode suppression ratio of 16dB single longitudinal mode narrow linewidth dual-wavelength output. The center the wavelengths 1565.1nm and 1567.4nm. At the same time, its interval of 2 minutes for 40 minutes, repeat the scan results show a very stable dual-wavelength laser wavelength shift and power fluctuations were less than 2pm and 0.4dB.

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