Study On The Light Transmission Characteristics Of Quantum Dot Fiber Amplifiers

The doped materials of traditional Fiber Amplifier are organic dyes or rare earth elements.In the past two decades,with studies of the performance of Fiber Amplifier doped by different elements,the performance of Fiber Amplifier had been greatly improved.However,the enabling potential of nature elements had already reached the limit,which should not meet the demand of higher bandwidth for all optical communication.It is necessary to look for a kind of Fiber amplifier with wider and better flat gain characteristics.Semiconductor nano-crystals quantum dots have attracted great interest over the past decades Owing to the electrons and holes in the quantum dots constrained in three dimensions,a series of quantum effects were emerged,such as quantum size effect,macroscopic quantum tunneling effect,surface effect and so on.Due to these unique physical and chemical properties differential from bulk materials,quantum dots have a wide application prospect in the fields of single electron devices,memory and various optoelectronic devices.InAs?InSb?GaSb etc nano-crystals are an ?-?semiconductors with good fluorescence characteristics in near infrared bands.Cd and Zn family quantum dots have good fluorescence characteristics in visible-near infrared band.What is more,quantum dots with different emission peak wavelengths can be obtained by changing the size of quantum dots.So full band communication from visible to the mid-infrared band will be obtained by choosing different kinds and sizes of quantum dots.This unique properties of quantum dots,especially the size dependence of absorption spectra and emission spectra,make quantum dots become a new type of optical gain medium.These superior properties are superior to natural elements.Therefore,using of quantum dots as optical gain medium and optical amplification medium in the field of optical fiber communication,which is a promising optical fiber amplifier.The optical fiber amplifier with using quantum dots as the gain medium and the transmission medium,which is different from the traditional optical fiber amplifiers with natural elements(such as erbium,ytterbium and thulium).From now on,there is little research on it at home and abroad.Therefore,the study of it is meaningful.In this paper,firstly,we had successfully synthesized colloidal ZnSe quantum dots by colloidal chemical method in oleic acid and paraffin system and synthesized quantum dots were characterized by means of absorption and fluorescent spectra,atomic force microscope,transmission electron microscopy,selected area electron diffraction and Fourier Transform Infrared Spectrometer.Then,with using colloidal ZnSe quantum dots as gain and transmitting medium and UV adhesives as the base material of ZnSe quantum dots,fiber doped by quantum dot was prepared via the method of the pressure difference.Lastly,the Bragg Grating was coupled at the two ends of the quantum dot doped fiber and quantum dot doped fiber amplifier was prepared.According to the principle of frequency selection and amplification of Bragg Grating,the fluorescence signal of quantum dots was amplified.