| Our learning and life style has thoroughly changed by the optical communication system, and will not reverse back in the near future. However, a big trouble has bothered the scientists since the optical communication system was applied, the signal loss of long distance transmission. In order to solve this problem, the optical amplifier was invented. Usually, Er3+ is widely used in the amplifier because of its 1.53 ÎĽm emission from the 4I13/2â†'4I15/2 radiative transition, this radiation occasionally dropped in the optical fiber interconnection low loss window. Er3+ doped fiber amplifier(EDFA) is the first device that applied in practice. Compared with EDFAs, the Er3+ doped waveguide amplifier(EDWA) can not only provide high gain in a much smaller device space, but also integrated with other silicon based optical devices. Many researchers has been trying to find a new material that could be used as matrix of EDWA. This matrix material could be inorganic crystals, glasses, polymer and so on. The advantages of polymer is easy to processing, allowing adjusting refractive index through changing the monomer component ratio. Also, the cost of EDWAs would be much lower by using polymer as its base matrix, it means the polymer based EDWAs could be easier to spread. Therefore, the dispersion of nanoparticles in the polymer is the key factor to a practical EDWA.At present, nanomaterials are physically doped in the polymer matrix with the help of ultrasonic. However, nanomaterials have strong surface activity, that means they are prone to agglomerate, forming large particles that scatter light, reduced the transparency of our waveguide material. Also, aggregation lowered the stability of NPs in the polymer, making the EDWA afford insufficient gain only. In order to overcome this defect, we carried on the following innovations:1, Using heterogeneous core/shell induction method, we prepared the Er3+ and Yb3+ co-doped core-shell structure alpha-NaYF4/ beta-NaLuF4 nano particles under solvothermal conditions. With the help of high resolution transmission electron microscopy and line scanning measurements, characteristics of this kind of particles were obtained. All the measurements proves the obvious core/shell structure. And the X-ray diffraction, Fourier Transform infrared absorption, photo luminescence and other measure equipment were also taken to detect nanoparticles’ features. Transmission electron microscope images showed that the average particle size is in 15~20nm range, particles are coated by the oleic acid group, and the sample can be well dispersed in cyclohexane, forming a clear solution. The NPs’ solution could emit bright upconversion light, and down shifting fluorescence of the sample was also very strong under the detection of SPEX 1000 M spectrometer.2, By the help of covalent bond, the core shell structure nanomaterial NaYF4/NaLuF4 :Yb, Er homogeneously dispersed in the PMMA matrix, obtained the transparent composite material. By changing the time of the copolymerization reaction, the material has the proper viscosity, and the optical waveguide device can be prepared by simply rotating the filling groove. The optical waveguide devices were observed a really high 22 dB relative gain. Both the relative gain and the stability of the device were improved obviously compared to the reported results so far. All the experimental results indicate that the copolymerization method is helpful to gain better waveguide amplifier. It has the potential value to be popularized. |
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