Net Brillouin gain in tellurite covered silicon nitride waveguides

We measure strong Brillouin gain in geometrically and cladding engineered structures of tellurite covered silicon nitride waveguide. Here we report gain values of 80.9 m-1W-1 and 76.2 m-1W-1, for structures with air and silica cladding, respectively. This gain signifies a 150 times improvement over previous silicon nitride based waveguides, and brings these platforms in the regime of net amplification needed for on-chip amplifiers. We demonstrate the amplifier by measuring a 10 dB Brillouin induced amplification overcoming the 4.7 dB of propagation loss incurred over the same length.