Heterogeneous integration of KY(WO 4 ) 2 -on-glass: a bonding study
Résumé
Rare-earth ion doped potassium yttrium double tungstate, KY(WO4)2, is a promising candidate for small, power-efficient, on-chip lasers and amplifiers. There are two major bottlenecks that complicate the realization of such devices. Firstly, the anisotropic thermal expansion coefficient of KY(WO4)2 makes it challenging to integrate the crystal on glass substrates. Secondly, the crystal layer has to be, for example,<1μm to obtain single mode, high refractive index contrast waveguides operating at 1550 nm. In this work, different adhesives and bonding techniques in combination with several types of glass substrates are investigated. An optimal bonding process will enable further processing towards the manufacturing of integrated active optical KY(WO4)2 devices.