Research On Rare Earth Doped Organic Optical Waveguide Amplifier Based On The Mechanism Of Intramolecular Energy Transfer

Based on the optical fiber communication technology,People built the globalization optical communication network.Because the long distance fiber communication will lead to the optical signal loss,people need a device to amplify the optical signals in the optical communication network,like the optical amplifier,this device can make up the optical signal loss by amplifying the damped optical signals to become the normal optical signals.As a kind of the optical amplifiers,rare earth doped organic optical waveguide amplifiers have the advantages of simple process,high integration,good optical gain and so on,it has become a hot research topic in recent years.Optical waveguide amplifiers usually use semiconductor lasers with wavelengths of 980nm or 808nm as the pumping source,the gain is achieved by population inversion according to the intrinsic absorption of the rare earth ions at these pump wavelengths.But the planar optical waveguide amplifiers made by rare earth doped organic material can use the LED light source of low cost and low power to replace expensive semiconductor laser as a pump sources,because the organic ligand has continuous and strong absorption at 200 nm to 450 nm wavelength,in this way it can reduce the cost of the device application,could be widely used.In this paper,the theoretical and experimental possibilities of applying the intramolecular energy transfer between organic ligands and central rare earth ions to planar optical waveguide amplifiers are presented.Two ytterbium-doped organic materials(Yb-DPE and Yb-DBT)and one erbium-doped organic material(ErQ3)were studied for their absorption,emission,film formation and other properties.The fabrication process of rare earth doped organic optical waveguide amplifier is discussed.The specific work is as follows:1.According to the intramolecular energy transfer mechanism between the organic ligand Q(8-hydroxyquinoline)and Er3+,the atomic rate equation and optical power transmission equation of erbium-doped organic optical waveguide amplifier are established,we simplified the equation based on overlap integral factor and runge-kutta method calculated the simulated gain.The results show that:When the length of the waveguide is 2cm and the size of the waveguide cross section is 3.6×10-11 m2,optical gain can be generated when the pump light power reaches 1mW under the excitation of 350nm LED,and when the pump light power reaches 3.5mw,the maximum theoretical gain is 5.4dB.2.ErQ3 powder was characterized by UV absorption spectra and fluorescence spectra excited by 350nm LD,the results show that ErQ3 has the intramolecular energy transfer mechanism,organic ligand can absorb the light energy in the blue ultraviolet band and transmit it to the central Er3+ion for 1535nm signal light amplification.We prepared the ErQ3-doped methyl methacrylate(PMMA)film,and characterized its UV absor:ption spectra.3.According to the intramolecular energy transfer mechanism between the organic ligandJDBT or DPE)and Yb3+,the atomic rate equation and optical power transmission equation of erbium-doped organic optical waveguide amplifier are established,we calculated the simulated gain.the results show that:When the length of the waveguide is 2cm and the size of the waveguide cross section is 3.6×10-11m2,positive gain can be generated when the pump light power reaches 1.5mW under the excitation of 405nmLED,and when the pump light power reaches 6mw,the maximum theoretical gain is 5.1dB.4.We prepared Yb-DBT-doped PMMA thin film and Yb-DPE-doped PMMA thin film.The powder of these two materials and thin films were characterized by UV absorption spectra,and fluorescence spectra excited by 405nm LD and LED.The results show that DBT and DPE have the intramolecular energy transfer mechanism with Yb3+,these two materials are expected to achieve 980nm(near-infrared band)optical amplification.5.We studied on ytterbium doped organic materials and erbium doped organic material for the condition of its applications in devices,designed and prepared the embedded optical waveguides for rare earth doped organic material,built the test system,observed the near-field spot of signal light at the output end of the waveguide.