On-chip hybrid integrated waveguide amplifier based on Er³⁺-doped fluorotellurite glass with 12 dB internal net gain

Erbium-doped glass, as a promising optical platform, offers great potential for fabricating high-efficiency waveguide amplifiers. However, integrating erbium-doped glass waveguide amplifiers with silica-based devices remains a critical challenge. Here, for the first time to the best of our knowledge, we propose an Er³⁺-doped fluorotellurite glass waveguide amplifier hybridly integrated onto a silica chip using pulsed laser deposition. We have achieved breakthrough progress in both the optical gain of glass materials and the design of optical waveguide structures. Specifically, we synthesized and fabricated an Er³⁺-doped fluorotellurite glass exhibiting a fluorescence lifetime as long as 4.42 ms. Furthermore, we propose, for the first time to the best of our knowledge, a hybrid integrated waveguide amplifier with a strip-loaded waveguide structure, where the planar layer is an Er³⁺-doped fluorotellurite glass thin film deposited by PLD and the strip-loaded waveguide is made of SU-8. The proposed amplifier exhibits a propagation loss as low as 1.92 dB/cm at 1550 nm. Owing to the high Er³⁺ doping concentration, an internal net gain of 12.23 dB is achieved under a pump power of 125 mW with a relatively short waveguide length of 0.4 cm, together with broadband signal enhancement across the C-band ranging from 1510 nm to 1570 nm.