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

As an excellent broadband tunable oscillation and amplification medium, Titanium-doped sapphire (Ti:Sapphire) has played an important role in basic research and technical application including experimental quantum optics, ultrafast lasers, precision atomic and molecular spectra, etc. However, the use of current Ti:Sapphire laser is severely limited by its large size, high cost and high pump power. Here, we design a Si3N4 on-chip broadband optical waveguide amplifier based on ion sliced Ti:Sapphire gain medium, with an ultra-wide bandwidth of 650 - 900 nm and peak gain of 28 dB. The finite difference method is used to optimize the characteristic parameters of the waveguide by combining the optical field limiting factor with the effective mode area to improve its gain performance. The device is designed to control the target thickness of Ti:Sapphire to 1 µm by using ion cutting technology, with Γs reaching nearly 80%. The obtained on-chip amplifier has the advantages of miniaturization, cost reduction and scalability. The effects of waveguide length, pump power and input signal power on the gain are analyzed under pump light of 532 nm. This work provides a basis for theoretical research and optimal design of on-chip Ti:Sapphire waveguide amplifier and laser.