Four-wave Mixing Multiwavelength Fiber Laser With Highly Erbium-Doped Fiber

Multiwavelength Erbium-Doped Fiber Laser(MWEDFL)is one of the most promising light sources in the field of optical communication.It has eliminated the shortcomings of traditional semiconductor laser arrays,such as complex operation,large structure and high cost.MWEDFL has high Gain,wide bandwidth,low insertion loss,simple structure,and broad gain curve which covers almost 1550 nm operating wavelength range of wavelength division multiplexing(WDM)system.So MWEDFL has broad application prospects in the fields of dense wavelength division multiplexing,optical fiber sensing,and optical measurement.However,a severe mode competition effect of light of each frequency causes it is difficult to effectively obtain a stable multiwavelength output because of uniform broadening characteristics.Therefore,how to further achieve stable multiwavelength output has important research significance.In this paper,a new type of highly erbium-doped fiber is used as the gain medium of the multiwavelength fiber laser.Four-wave mixing(FWNM)is used to suppress the mode competition of the laser.A design and experimental study is carried out.The FWM multiwavelength erbium-doped fiber laser with ring-cavity effectively reduces the cavity length and improves the output wavelength stability,flatness and side-touch suppression ratio.The experimental results show that a stable output of 16 wavelengths has been realized with a highly erbium-doped fiber which is only 62 cm and the maximum average power variation within 3 dB is only 0.08 dB,the average side mode suppression ratio(SMSR)is greater than 33 dB.The main contents are as follows:1.The gain characteristics of quartz-based erbium-doped fiber are studied in depth.Combined with the Giles model,the time domain model of the laser using erbium-doped fiber as the gain medium is established.The variation of output optical power and the concentration of the upper level particles are simulated.2.For the mode competition problem,this chapter studies how to use the FWM effect in the ring-cavity to transfer the energy between each output light.And then,cross-phase modulation(XPM)in a nonlinear optical loop mirror(NOLM)is used to further suppress the mode competition.A two-wavelength lasing with FWM and Lyot comb filter are studied by simulation.3.The experimental platform of a four-wave mixing multiwavelength fiber laser using a new highly erbium-doped fiber is built The gain characteristics of two kind highly erbium-doped fibers are experimentally studied compared to another.The lasing spectrum with 16 wavelengths and 12 wavelengths in the range of 3 dB is obtained experimentally,and the corresponding experimental results are qualitat:ively analyzed with a pump power of 500 mW.4.A nonlinear fiber loop mirror is introduced to optimize the experimental structure.The flatness of the output spectrum and the indicators such as SMSR are studied.The stability of the experimental system is analyzed by taking three peak light waves near the center wavelength as an example.