Improved Process for Room-temperature Bonding Multiple GaAs Thin Plates to Develop Wavelength-conversion Devices

Improved fabrication process enables us to reduce the internal scattering loss of a quasi-phase-matching (QPM) stack of multiple GaAs thin plates. This is accomplished by setting GaAs plates on YAG crystals with laser-grade flat surfaces. The loss per interface (at 1.5 μm) of the fabricated 25-plate stacked GaAs QPM device is 1.8 %, which is 70 % smaller than the 11-plate stack fabricated with the previous process.