Fabrication of Yb~(3+)/Er~(3+) codoped Bi_2O_3-WO_3-TeO_2 pedestal type waveguide for optical amplifiers

摘要

We report, for the first time to our knowledge, experimental results on pedestal waveguides produced with Yb~(3+)Er~(3+) codoped Bi_2O_3-WO_3-TeO_2 thin films deposited by RF Sputtering for photonic applications. Thin films were deposited using Ar/O_2 plasma at 5 mTorr pressure and RF power of 40 W on substrates of silicon wafers. The definition of the pedestal waveguide structure was made using conventional optical lithography followed by plasma etching. Propagation losses around 2.0 dB/cm and 2.5 dB/cm were obtained at 633 and 1050 nm, respectively, for waveguides in the 20-100 μm width range. Single-mode propagation was measured for waveguides width up to 10μm and 12 μm, at 633 nm and 1050 nm, respectively; for larger waveguides widths multi-mode propagation was obtained. Internal gain of 5.6 dB at 1530 nm, under 980 nm excitation, was measured for 1.5 cm waveguide length (～3.7 dB/cm). The present results show the possibility of using Yb~(3+)/Er~(3+) codoped Bi_2O_3-WO_3-TeO_2 pedestal waveguide for optical amplifiers.