Research On Mid-infrared Supercontinuum Sources Based On All-solid Fluorotellurite Fibers

2-5?m mid-infrared supercontinuum?SC?light sources have attracted much attention due to their numerous applications in frequency metrology,molecular spectroscopy,biomedicine,defense,and security.All-fiber SC light source has attracted extensive attention due to its compact structure,strong anti-interference ability and good beam quality.In our previous work,we have developed a new type of mid-infrared fluorotellurite?TeO₂-BaF₂-Y₂O₃,TBY?glass fiber.It has higher chemical stability and laser damage resistance compared with previously reported tellurite glass fiber,fluoride glass fiber and chalcogenide glass fiber.Preliminary results show that fluorotellurite fibers are potential non-linear medium for developing broadband,high power mid-infrared SC light source.During the doctoral years,the author has worked on the broadband,high power mid-infrared SC light sources from all-solid fluorotellurite fibers.The author achieved a series of research results as follows:?1?For the first time,broadband SC light source with spectral coverage of 600-5400 nm has been realized in tapered all-solid-state fluorotellurite glass fibers.In this work,all-solid-state fluorotellurite glass fibers with core diameter of 6?m were fabricated by rod-and-tube method,and the tapered fluorotellurite glass fibers with dispersion-decreasing were fabricated by combining with tapering technology.By using the tapered fiber as nonlinear medium and the 2010 nm femtosecond fiber laser as a pumping source,SC light source with spectral range of 600-5400 nm has been realized.This is the widest SC spectrum obtained in fluorotellurite glass fiber.When the pump power is 1.57 W,the output power of SC light source is about 0.85 W,and the corresponding optical-optical conversion efficiency is about 54.1%.?2?SC light source with an average output power of 22.7 W and a spectral range of 1000-3950 nm was constructed by using all-solid-state fluorotellurite glass fiber as a nonlinear medium.In this work,by using a 60 cm long all-solid-state fluorotellurite glass fiber with core diameter of 11?m as nonlinear medium,and a homemade 2?m high-power ultra-short pulse fiber laser as pumping source,SC generation from 1000to 3950 nm is obtained,the corresponding output power is about 22.7 W for an average pump power of³9.7 W,and the corresponding optical-optical conversion efficiency is about 57.2%.In addition,no obvious damage of the fluorotellurite fiber was observed during the operation of the above SC light source.?3?Mid-infrared Raman soliton lasers with tunable bandwidth from 1.96 to 2.82?m are obtained by using a negative dispersion all-solid-state fluorotellurite glass fiber as the nonlinear medium.By using a 0.5 m long all-solid fluorotellurite fiber with a core diameter of².7?m as the nonlinear medium and a 1960 nm femtosecond fiber laser as the pump source,tunable mid-infrared Raman solitons generation from 1.96 to 2.82?m are obtained via soliton self-frequency shift.For the soliton laser source operating at 2.82?m,the calculated pulse width is about 93 fs and the obtained optical-to-optical conversion efficiency is about 18%.