The Study Of 1.5?m Erbium-doped Ultrashort Pulse Mode-locked Fiber Laser

Ultrashort fiber lasers are widely used in a variety of industry area including medical imaging,measuring distance,ophthalmology,laser weapons,laser micromachining,precision metrology,and etc.At the same time,it is a powerful tool in scientific research for us to learn about the transient phenomena and processes in nature.In this paper,we utilize the scheme of nonlinear polarization evolution(NPE)to realize a systematic research of Erbium doped fiber laser and Erbium-ytterbium(Er/Yb)co-doped fiber laser.The research results of this paper are as follows:1?We introduce the basic equations of optical wave transmission in optical fiber in theory,and the nonlinear schr?dinger equation is deduced.Secondly,the dispersion effect and nonlinear effect of optical fiber are introduced,and the influence on pulse transmission is discussed.After then,the mode locking principle and basic structure of the mode-locked fiber laser is introduced,we analyze the characteristics of the basic structure of the mode locked fiber laser and explain the scheme of NPE and the mode locking principle carefully.Finally,the fiber lasers with different mode locking mechanisms are compared and analyzed.2?Based on NPE mode locking technique,an experimental research of 1.5 ?m single mode Erbium-doped mode locking fiber laser was carried out.Firstly,the stable conventional soliton mode locking pulse with the repetition frequency of 51.02 MHz,the full width at half maximum of 39 nm,the pulse width of 2.57 ps,the peak power of 241.2W was generated at a central wavelength of 1558.6 nm;we also realize stable bound state mode locking pulse output for further adjusting wave plates in experiment and analyze the characteristics of the output pulse;based on it,we achieve stable dispersion managed soliton output in experiment by using different dispersion compensation fiber to conduct dispersion management of fiber cavity.3?Based on NPE mode locking technique,an experimental research of 1.5 ?m double cladding Er/Yb co-doped mode locking fiber laser was carried out.A double cladding fiber laser is set up in the experiment,the stable noise-like mode locking pulse with the fundamental repetition frequency of 11.34 MHz,the full width at half maximum of 15 nm,the pulse width of 125.7 fs was generated at a central wavelength of 1560 nm by adjusting dispersion and polarization of cavity,at the pump power of 8 W,the high-order harmonic noise-like pulse is 115 GHz and the maximum output power of the laser is 628 m W.