A novel design of multi-pass pumped Yb:YAG planar waveguide amplifier waveguide amplifier

We present a novel structure of planar waveguide for Yb:YAG laser amplifiers allowing large absorption length. The structure parameters of the planar waveguide were optimized using an 3D amplification model. The performance of the optimized planar waveguide laser amplifier was simulated, and a comparison between the cases with and without considering pump saturation was carried out. The simulated results show that a high pump absorption efficiency and optical-to-optical efficiency can be expected in addition to a good absorption uniformity. The seeder power is scaled from 200W to 7000W, the corresponding pump absorption and optical-to-optical efficiencies are 98.6% and 68%, respectively. The thermal stress of the designed planar waveguide is analyzed theoretically, the results show that the pump power of 10kW is available without the fracture risk.