Fabrication of YAG/Yb:YAG Microchip/Yb:YAG Composite MOPA Using Room-Temperature Bonding

Thermal effects, including thermal lens and thermally induced birefringence are serious problems in solid-state lasers since they decrease laser power and efficiency, degrade beam quality, and ultimately lead to catastrophic damage. Composite lasers consisting of laser-ion-doped and undoped materials can reduce the thermal effects by efficiently transferring the heat generated in the doped region to the undoped segment. Although the diffusion bonding has been mainly used for fabricating composite structures [1], its high-temperature process makes it difficult to bond materials with different thermal-expansion coefficients. On the other hand, we are developing composite lasers using the room-temperature bonding [2].