High-gain waveguide amplifiers in Si3N4 technology via double-layer monolithic integration

Abstract

Silicon nitride ( Si 3 N 4 ) - on - SiO 2 attracts increasing interest in integrated photonics owing to its low propagation loss and wide transparency window, extending from ∼ 400 nm to 2350 nm. Scalable integration of active devices such as amplifiers and lasers on the Si 3 N 4 platform will enable applications requiring optical gain and a much-needed alternative to hybrid integration, which suffers from high cost and lack of high-volume manufacturability. We demonstrate a high-gain optical amplifier in Al 2 O 3 : Er 3 + monolithically integrated on the Si 3 N 4 platform using a double photonic layer approach. The device exhibits a net Si 3 N 4 - to - Si 3 N 4 gain of 18.1 ± 0.9 dB at 1532 nm, and a broadband gain operation over 70 nm covering wavelengths in the S-, C- and L-bands. This work shows that rare-earth-ion-doped materials and in particular, rare-earth-ion-doped Al 2 O 3 , can provide very high net amplification for the Si 3 N 4 platform, paving the way to the development of different active devices monolithically integrated in this passive platform.