Research On Fiber Laser Based On TiS₃ As Saturable Absorber

Fiber lasers have higher peak power.With the increasing development of modern science and technology,ultra-short pulse light sources are in great demand in the areas of laser ranging,high-speed photography,lidar,and high-resolution spectroscopy.In recent years,two-dimensional layered materials because they have excellent photoelectric characteristics and unique structural characteristics that are different from general bulk materials and have become one of the hot spots of research in recent years.Based on the above research background,this paper conducts research on fiber lasers based on TiS3 as a saturable absorber(SA).TiS3-SA was prepared by Chemical vapor transport(CVT)-mechanical stripping method-wet transfer.Using its saturable absorption characteristics,stable Q-switched sequences and mode-locked pulses were achieved in the fiber laser,respectively.The experimental results were analyzed and discussed.The specific research content is as follows:1.Investigation of fiber lasers and 2D materialsIn the pre-investigation stage,this article summarizes the research status of fiber lasers.According to the types of pulsed lasers,it is divided into Q-switched lasers and mode-locked lasers.The principles and methods of Q-switched and mode-locked lasers are investigated and introduced in detail.The emphasis is on the mechanism of passiveQ-switching and passive mode-locking.In addition,the development status and common materials of two-dimensional materials used as saturable absorber access fiber lasers are also introduced in this article.2.Implementation of TiS3 Q-switched Er-doped fiber laserTheQ-switched erbium-doped fiber laser based on TiS3-SA was studied.The SA with a saturable absorption of 39.03%was prepared.The prepared TiS3-SA was modulated in an erbium-doped fiber laser to obtain the Q-switched sequence pulse with the center band of 1550 nm.When the pump power is increased from 160mW to 630mW,the repetition frequency of the laser is increased from 102.2kHz to 257.6kHz,the signal-to-noise ratio is 50dB,and the maximum single pulse output energy is 38.9nJ.The narrowest pulse width of the laser output is 506ns,which also proves that TiS3 has certain potential in the field of ultrafast photonics as a nonlinear optical material.3.Implementation of TiS3 mode-locked erbium-doped fiber laserIn order to continue to study the optical and electrical properties of the new transition metal chalcogenide TiS3,we prepared TiS3 by CVT-mechanical peeling method,and characterized it using Atomic Force Microscope,Raman spectroscopy,etc.,and tested its nonlinear characteristics.It is found through fitting that the modulation depth of TiS3 prepared by us can reach 39.39%,and the saturable absorption light intensity is 1.646MW/cm2.We have built a passive mode-locked erbium-doped fiber laser based on TiS3-SA to obtain a mode-locked pulse output with a center wavelength near 1555 nm and a narrowest pulse width of 147.72 fs.The laser works stably.The experimental results show that TiS3 can be used as a saturable absorber of pulsed fiber laser,and has great research potential in the field of ultrafast optics.