Study On Multi-Wavelength Fiber Lasers And Their Applications

Dense Wavelength Division Multiplexing (DWDM) technology, which cangreatly improve the transmission capacity, has become one of the most importanttechnologies in the optical communication networks. In order to meet the requirementof the multi-channels, the traditional solution is to increase the quantity of the lasers,which undoubtedly increase the cost and complexity. In recent years, multi-wavelengthfiber lasers have become the research focus for their attracting advantages in DWDMsystems, such as narrow line width, multi-wavelength output, low cost, easy tofabrication, large turning range, and so on.In this thesis, on the basis of theoretical analysis and numerical simulations, we dosome research on multi-wavelength fiber lasers and their applications by the experiment.The major achievements and innovative results of this thesis are summarized as follows:1、The reflection and transmission characteristics of Sagnac loop based onhigh-birefringence (HiBi) fibers are deduced. A tunable multi-wavelength ring fiberlaser is proposed based on the Sagnac loop. For the single and cascaded Sagnac loop,the effects of the length of the PMF and the states of the PCs on the reflective spectrumare analyzed by the theory, respectively. In the experiment, the single- andmulti-wavelength are obtained by adjusting the PCs, besides, the relationship betweenthe 3dB linewidth of the laser and the length of PMF are also verified.2、A tunable multi-wavelength ring fiber laser based on Stimulated Brillouinscattering (SBS) is presented. By using the linear gain of the erbium-doped fiber (EDF)and the Brillouin gain, a multi-wavelength laser with spacing of 0.088nm (11GHz) canbe obtained. In the experiment, a stable multi-wavelength (wavelength spacing is0.088nm) is produced within a ~40nm wavelength tuning range by changing thewavelength of the Brillouin pump, the experiment also demonstrate the relationshipbetween the output power of the 980nm laser diode (LD) and the quantity of thewavelengths.3、Using the fiber Bragg grating pair (FBGP) as the wavelength-selectivecomponent and a segment of PM-EDF as a narrow multi-band filter, a simpledual-wavelength ring cavity fiber laser operating in single-longitudinal-mode at roomtemperature is achieved. Dual-wavelength with different spacing (0.212nm、0.308nm、 0.392nm、0.444nm) are observed by using different FBGP, and the optical signal tonoise ratio (OSNR) of each state is greater than 50dB.4、Starting with the interference of light, the principle of photonic generation of themicrowave signal is discussed. On the basic of ring cavity dual-wavelengthsingle-longitudinal-mode fiber laser, by turning the PCs to enhance the polarization holeburning (PHB), dual-wavelength laser oscillations with the wavelength spacing of0.212nm are observed. Finally, by beating the dual-wavelength at a photodetector (PD),a microwave signal at 26.44GHz is generated.