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Study On Rare Earth Ions Doped Fluoride Nanoparticles For Polymer-based Waveguide Amplifiers

Posted on:2017-01-02Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y L ZhangFull Text:PDF
GTID:1108330482491886Subject:Microelectronics and Solid State Electronics
Abstract/Summary:PDF Full Text Request
The polymer waveguide amplifiers show the great potential of application in the field of photonic communication since they are easy to process, costing low to manufact, easy to adjust refractive index, easy to integrate with silicon-based planar, and possess good mechanical properties, etc. At present, the polymer waveguide amplifiers based on rare-earth complexes have obtained a net gain in the corresponding amplification band. The stability of the the polymer waveguide amplifiers based on rare-earth complexes are poor due to the optical bleaching of rare-earth complexes. Rare-earth doped fluoride nanocrystals are ideal gain mediums due to excellent optical stability, long fluorescence lifetime, and pumping by near-infrared light, which can overcome the defects of the rare-earth complexes. In addition, we can make the polymer waveguide amplifiers which suitable for different wave band(1.5mm, 0.6mm) by changing the doping species of the rare-earth ion. To obtain high optical signal gain, we need to synthesize the fluoride nanocrystals with the good the dispersion of nanocrystals, the small the size, the large the luminescence intensity, because the gain of the polymer waveguide amplifiers can be influenced by dispersion, size and luminescence intensity of the fluoride nanocrystals. The rare earth doped fluoride nanocrystals for the polymer waveguide amplifiers has many defects in the size, luminescence intensity and dispersion of the nanocrystals. Therefore, preparing rare-earth doped fluoride nanocrystals with good dispersion, small size and large luminescence intensity is an urgent problem to be studied.This paper carried out a systematic study on rare earth ions doped fluoride nanoparticles for polymer-based waveguide amplifiers. The research results are as follows:1. In order to synthesize the rare earth doped fluoride nanocrystals with favourable dispersibility, small size and high luminescence for waveguide amplifiers at 1.5 mm, we proposed a layer-by-layer strategy to improve the luminescence intensity of small size fluoride nanocrystals. The Ba Lu F5: Yb3+, Er3+@(X-shell, X=15) Ba Lu F5: Yb3+ NPs were synthesized via a high boiling solvent process through a layer-by-layer strategy. Up-conversion and down-conversion fluorescence spectra of the NPs were measured by using a 976 nm laser diode as the excitation source. In comparison with optical properties of Ba Lu F5: Yb3+, Er3+ NPs, the intensities of up-conversion(545 nm) and down-conversion(1530 nm) fluorescence were enhanced by 52 and 9.8 times after coating 5-layer active-shells(Ba Lu F5: Yb3+) on the Ba Lu F5: Yb3+, Er3+ NPs, respectively. The UC and DC emissions of the Ba Lu F5: Yb3+, Er3+@(5-shell)Ba Lu F5: Yb3+ NPs with multi-layer active-shells were 1.3 and 1.1 times larger than that of the Ba Lu F5: Yb3+, Er3+@ Ba Lu F5: Yb3+ NPs with a one thick-layer active shell, respectively. Our experimental results showed that multi-layer active-shells could be used to not only suppress surface quenching but also transfer the pump light to the core region efficiently through Yb3+ ions inside the active-shells. The Ba Lu F5: Yb3+, Er3+@(5-shell) Ba Lu F5: Yb3+ NPs doped SU-8 polymers, the polymer-based waveguide amplifiers were constructed, a relative optical gain of 3.13 d B was obtained at 1530 nm.2. At present, red waveguide amplifiers at 0.6 mm based on fluoride nanocrystals have not yet been reported. We constructed red waveguide amplifiers based on fluoride nanocrystals,a relative optical gain was obtained at 650 nm. The KMn F3: Yb3+, Er3+ NPs were synthesized via a solvothermal method. With the excitation of a 976 nm laser diode, bright red up-conversion fluorescence(4F9/2→4I15/2) was observed from KMn F3: Yb3+, Er3+ NPs owing to the existence of efficient energy transfer between Er3+ and Mn2+:2H11/2, 4S3/2+6A1→4I15/2+4T1, 2H9/2 +6A1→4I13/2+4T1 and 4I15/2 +4T1→4F9/2+6A1. Then, the KMn F3: 18 % Yb3+, 1 % Er3+ @ KMn F3: 2 % Yb3+ NPs via coating an active-shell were synthesized via coating an active-shell strategy. By using the active-core-active-shell NPs as the gain medium and doping NPs into a polymer waveguide, we constructed polymer-based waveguide amplifiers. we reported optical amplification at 650 nm in a polymer waveguide amplifier based on the active-core-active-shell NPs for the first time. A relative optical gain of 3.5 d B was obtained at 650 nm.3. In order to construct the broadband waveguide amplifiers at 1.5 mm, the rare-earth doped fluoride nanocrystals need to have favourable dispersibility, high luminescence and broadband near infrared emission property. We synthesized a KMn F3: Yb3+, Er3+ NPs with broadband down-conversion emission property via a solvothermal method. With the excitation of a 976 nm laser diode, KMn F3: Yb3+, Er3+NPs shows two emission peaks at 1.5 mm. The full width at half maximum(FWHM) of fluorescence spectra of KMn F3: Yb3+, Er3+ NPs was wider14 nm than that of Na YF4: Yb3+, Er3+ NPs. We proposed an approach to improve the intensity of down-conversion fuorescence of KMn F3: Yb3+, Er3+ NPs by coating shell containing Yb3+ ions. Then,we successfully synthesized KMn F3: 18 % Yb3+, 1 % Er3+@ KMn F3:2 % Yb3+ NPs via a coating method. By using the active-core-active-shell NPs as the gain medium and doping NPs into a polymer waveguide, we constructed polymer-based waveguide amplifiers. A relative optical gain of 0.6 d B was obtained at 1534 nm.
Keywords/Search Tags:Nanocrystals, Up-conversion, Down-conversion, Polymer waveguide amplifiers
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