On-chip Er-doped Ta₂O₅ waveguide amplifiers with a high internal net gain

We designed and fabricated a double-layered structure Er³⁺:Ta₂O₅ waveguide and investigated its optical amplification performance in C band. The pump laser threshold for zero gain at 1533 nm was 2.5 mW, and the internal net gain was ∼4.63 dB/cm for a lunched pump power of 36.1 mW at 980 nm and signal input power of -30.0 dBm (1 µW). The relationship between the internal gain and the signal input power was also investigated, and a large internal net gain of 10.58 dB/cm was achieved at a signal input power of ∼-47.1 dBm. The results confirm the potentials of the use of Ta₂O₅ as a host material for optical waveguide amplification.