Polymer Waveguide Amplifiers Based On Er³⁺-Yb³⁺ Co-doped Core-shell Nanocrystals

Rare earth doped optical amplifiers can achieve the optical amplification directly with the stimulated radiation process. Erbium doped waveguide amplifiers（EDWAs） have attracted much attention in recent years, due to its potential application for the development of optical communication technology. EDWA based on organic polymer materials has excellent properties, such as simple processing, potentially low cost and potential application for silicon integration, which make it win the important application in the planar photonic integration and short distance optical communication system.In this thesis, gain characteristics of waveguide amplifiers based on SU-8 2005 doped with Na YF4: Er³⁺, Yb³⁺ nanocrystals（NCs） at 1.55μm wavelength were investigated by combining the power propagation equations with the atomic rate equations. We fabricated the waveguide amplifier with SU-8 doped with Na YF4: Er³⁺, Yb³⁺ nanocrystals. For input signal power of 0.1m W and 980 nm pump power of 170 m W, a relative optical gain of 3.4d B/cm at 1550 nm was obtained.In order to overcome the disadvantages of traditional physical doping method that the concentration of Er³⁺ in polymer matrix could not be high to avoid aggregation and the long-term stability of devices was not so good, in this thesis, the Na Lu F4: Er³⁺, Yb³⁺ NCs-PMMA covalent-linking nanocomposite and a new core-shell Na YF4/Na Lu F4: Er³⁺, Yb³⁺ NCs-PMMA covalent-linking nanocomposite were synthesized by copolymerization of the oleic acid-modified NCs with methyl methacrylate（MMA）. The optical waveguide amplifiers with an embedded structure were fabricated by filling the NCs-PMMA covalent-linking nanocomposites into PMMA cladding grooves. When the input signal power was 0.1m W and the 980 nm pump power was 160 m W, the optical waveguide amplifiers based on Na Lu F4: Er³⁺, Yb³⁺ NCs-PMMA and Na YF4/Na Lu F4: Er³⁺, Yb³⁺ NCs-PMMA covalent-linking nanocomposite obtained the relative gain of 5.8d B/cm and 7.9d B/cm at 1530 nm, respectively.