Research On Fiber Lasers And Four-wave Mixing Based On Two-dimensional Te-Se Heterojunctions

Fiber laser have good beam quality and compact structure,and the external environment has little influence on the fiber laser because the laser emission was bounded into the fiber,and the fiber has excellent heat dissipation.Pulsed fiber lasers have important applications in the fields of fiber communication,defense and military security,medical health,micromachining,marking,welding and cutting.Using saturable absorber as a key device for passively Q-switched and passively mode-locked technique is an important means for generating ultrashort pulsed lasers with nanosecond(ns),picosecond(ps),and even femtosecond(fs).All-optical wavelength conversion is one of the key technologies to realize all-optical communication.At present,all-optical wavelength conversion technology is based on non-linear effect,all-optical wavelength converter based on four-wave mixing has attracted many scientists' attention for its' excellent characteristics.Compared with other all-optical wavelength converters,the new wavelength based on four-wave mixing can completely replicate the amplitude,frequency and phase information of the signal light,and achieve fully transparent wavelength conversion.Wavelength conversion based on four-wave mixing was proposed as early as ten years ago.However,due to the limitation of the medium's non-linear strength,the conversion efficiency has been low.It is urgent to find a medium with high stability and non-linear strength.Recently,we discovered a heterostructure composed of two-dimensional materials,tellurene(Te)and selenene(Se),and formed a new two-dimensional Te-Se heterojunction material.This new two-dimensional material not only has better non-linear characteristics and better thermal conductivity than the original tellurene and selenene,but also has the ultra-high stability lacked by tellurene and selenene.In this thesis,the non-linear characteristics of the two-dimensional Te-Se heterojunction are combined with micro-nano fibers to achieve ultra-short pulse output on erbium-doped and erbium-doped passive mode-locked fiber lasers,and four-wave mixing Effect to achieve all-optical wavelength conversion,the main research contents are as follows:1.The characteristics and basic principles of fiber laser mode-locked and all-optical wavelength conversion technology are introduced,and the basic principles and measurement methods of saturable absorbers are introduced.2.The structure of the two-dimensional Te-Se heterojunction material was introduced,and the two-dimensional Te-Se heterojunction material was characterized by atomic force microscope(AFM),transmission electron microscope(TEM),and Raman spectroscopy.3.A fiber laser mode-locking experiment based on a two-dimensional Te-Se heterojunction material was introduced.A 11.7 ps mode-locking pulse was successfully obtained in an erbium-doped fiber laser,and an ultra-short mode-locking pulse of 889 fs was obtained in an erbium-doped fiber laser.4.An all-optical wavelength conversion experiment based on a two-dimensional Te-Se heterojunction material is introduced.The construction of a wavelength conversion experimental device is introduced.The performance and signal processing capabilities of the device are analyzed,and a 10 GHz signal modulation is successfully achieved.