Design of a broadband Si₃N₄ waveguide amplifier based on a gain medium of ion-sliced titanium-doped sapphire

In recent years, significant progress has been made in the on-chip integration of Ti:sapphire amplifiers and lasers, showing great potential in device miniaturization, cost reduction, and mass production. However, the further integration of such devices on standard CMOS platforms has been challenging due to its limits on the wafer bonding method between gain materials and substrates. Here, we present a novel, to the best of our knowledge, Si₃N₄ on-chip broadband optical waveguide amplifier scheme with an ultra-wide bandwidth of 650-900 nm and a peak gain of 28 dB based on an ion-sliced Ti:sapphire platform. The difficulty of heterogeneous integration is significantly reduced by growing Si₃N₄ thin films on Ti:sapphire. Moreover, by using homogeneous bonding combined with ion slicing technology, the target thickness of Ti:sapphire is expected to be easily controlled to less than 1 µm, greatly reducing the device volume and improving its practicality. Through subsequent experimental optimization, this work is expected to provide a new approach for the optimized design and experimental realization of on-chip Ti:sapphire waveguide amplifiers and lasers.