| Chalcogenide glass materials have high linear and non-linear refractive index,wide transmission range(up to 25 ?m),low phonon energy and fast non-linear response time,and thus they are potential applications in all-optical signal regeneration,OTDM signal optical demultiplexing and some integrated optical devices.Nonlinear optical waveguides based on chalcogenide glass(Ch Gs)have been proved to be very suitable for high-speed all-optical signal processing of communication signals.However,there is a problem of low conversion rate in the signal processing.Therefore,Erbium-doped chalcogenide waveguide amplifier(EDWA)is attracting wide attention since it can simultaneously process passive non-linear signal and amplifies online active signal.However,no net gain output in Er-doped chalcogenide optical waveguide technology is a serious issue.The fundamental reason is that the concentration of Er3+ is low.To solve this problem,we investigated the relationship between the solubility of rare earth ions(REI)and the composition and structure of chalcogenide glass by analyzing the local environment of Er3+.This thesis aimed at optimizing the composition of Er3+ doped chalcogenide glass and improving the solubility of Er3+ so as to effective increase the optical gain per unit length of waveguide.Therefore,the research contents can be summarized as follows:1.We fabricated samples doped with different Er3+ concentration in Ge20Ga5Sb10Se65 glass matrix and samples doped with 1.0 wt% concentration in Ge20Ga10S70 and tested their thermodynamic and optical properties.It was found that the density and refractive index of the sample increased slightly with the increase of Er3+ doping concentration in Ge20Ga5Sb10Se65,but the thermal stability and structure did not change significantly;when the concentration of 1.1 wt%,the fluorescence intensity was the strongest at 1.54 ?m and 2.78 ?m,and the fluorescence lifetime was about 2.23 ms at 1.54 ?m(4I13/2 energy level).2.The chalcogenide glass samples of Ge20Ga5Sb10Se65-1.0Er and Ge20Ga10Se70-1.0Er were microcrystallized and their properties were studied.The density and refractive index of the glass sample increase slightly with the increase of the time of microcrystallization treatment,and the transmittance in near infrared band decreases gradually.In the Ge20Ga5Sb10Se65-1.0Er sample,the fluorescence intensity is about 7 times higher than that of the untreated sample at 1.54 ?m,and the fluorescence intensity increases to ~2.95 ms.In Ge20Ga10Se70-1.0Er samples,with the precipitation of Ga2S3 and Ge S2 phases by the order,the fluorescence intensity increased to 2 times of the original at 2.78 ?m and then decreased.At the same time,the precipitation of nanocrystalline phase changed the internal structure of the glass samples.But both of them still maintain good transmittance in mid-infrared band.3.In suitable microcrystallized Ge20Ga10Se70-1.0Er samples,the specific distribution of Er3+ in the samples was characterized by high resolution transmission electron microscopy.The tested sample was prepared by focused ion beam(FIB).From the overall morphology,it can be seen that Ga2S3 crystalline phase is uniformly distributed in the whole amorphous region with a size of about 50 nm and S element is uniformly distributed.At the same time,combining with the results of line scanning,surface scanning,XRD and fluorescence intensity,it is concluded that Er3+ is mainly related to Ga2S3 crystal in the microcrystallized samples,and may be bonded in the form of Ga-Er or Ga-S-Er.Finally,we mainly summarizes the research results obtained in this work,and gives the deficiencies of this work in the research process and prospects for future research. |
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