The Basic Study On Nd³⁺ Doped Polymer Planar Optical Waveguide Amplifiers

Optical waveguide amplifier is a kind of device which can amplify optical signals and compensate the transmission loss. Optical waveguide amplifier has extremely prospect in optical fiber communication, integrated optoelectronics and integrated optics. Rare earth doped waveguide amplifier is the research focus recently. There are three main peaks at900,1060and1330nm in the luminescence spectrum of Nd3+ions, thus neodymium-doped amplifiers has great potential. This paper studies the Nd3+-doped polymer waveguide amplifier, particular contents are as follows:1. Aneodymium complex, Nd(TTA)3(TPPO)2(HTTA:2-thenoyltrifluoroacetone, TPPO:triphenylphosphine oxide) was synthesized and doped into PMMA (Polymethylmethacrylate) and SU-8. The absorption and photoluminescence spectra of the copolymer were measured. Using the Judd-Ofelt theory, the spontaneous transition probability, radiative lifetime, absorption cross sections, and emission cross sections of Nd(TTA)3(TPPO)2doped PMMA copolymer were calculated. With these parameters and fundamental rate equations and power propagation equations the gain of waveguide was simulated, and the relationship of the gain with them had been discussed. The small signal gain at1060nm calculated in a3-cm-long sample with a Nd3+concentration of0.5×1020cm-3was4.25dB/cm.2. The preparation of polymer waveguides were discussed, neodymium-doped polymer waveguide amplifiers were designed and fabricated. The ridge and embedded type of neodymium-doped PMMA and SU-8polymer waveguide amplifiers were designed and prepared, and also the morphology of neodymium-doped polymer amplifiers were characterized.3. The gain testing system was constructed and used to test the SU-8polymer waveguide and neodymium-doped SU-8and PMMA polymer waveguides. The results showed that these devices had good performance in terms of light through. The problem of coupling the signal of1064nm with pump light of808nm was sovled, the gain of the ridge type Nd(TTA)3(TPPO)2doped SU-8waveguide amplifier was tested. The small-signal gain measured in a12-mm-long sample with a Nd3+concentration of0.586×1020cm-3was0.35dB at1066nm, when the pump power was120mW and the signal power was4mW, thus a gain of0.29dB/cm was obtained.