Fabrication of Y-Splitters and Mach-Zehnder Structures on (Yb, Nb):RbTiOPO4/ RbTiOPO4 Epitaxial Layers by Reactive Ion Etching

Identifier:  PC:2908

Handle: https://hdl.handle.net/20.500.11797/PC2908

Authors:  Solé, R.; Butt, M.A.; Pujol, M.C.; Ródenas, A.; Lifante, G.; Choudhary, A.; Murugan, G.S.; Shepherd, D.P.; Wilkinson, J.S.; Aguiló, M.; Díaz, F.

Abstract:
Reactive ion etching of RbTiOPO4 (001) substrates and (Yb,Nb):RbTiOPO4/ RbTiOPO4 (001) epitaxial layers has been performed using fluorine chemistry. A maximum etch rate of 8.7 nm/m was obtained, and the deepest etch achieved was 3.5 m. The (Yb,Nb)-doped epitaxial layers showed a slower etching rate when compared with undoped material. Liquid phase epitaxial growth of cladding layers has also been performed, resulting in a high-quality interface growth without appreciable defects. 9-mm-long Mach Zehnder interferometer (MZI) and 9-mm-long Y-splitter structures were designed and patterned in RbTiOPO4 substrates and (Yb,Nb):RbTiOPO4/RbTiOPO4(001) epitaxial layers. The structures fabricated in RbTiOPO4 substrates were filled with laser active (Yb,Nb):RbTiOPO4 higher refractive index core material, and finally an RbTiOPO4 cladding was grown on the samples. The refractive index difference between the (Yb,Nb):RbTiOPO4 layer and the RbTiOPO4 substrate at 1.5 µm has been measured and optical waveguiding at this wavelength has been demonstrated