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

Identifier:  imarina:9241970

Handle: https://hdl.handle.net/20.500.11797/imarina9241970

Authors:  Butt, MA; Solé, R; Pujol, MC; Ródenas, A; Lifante, G; Choudhary, A; Murugan, GS; Shepherd, DP; Wilkinson, JS; Aguiló, M; Díaz, F

Abstract:
Reactive ion etching of RbTiOPO4 (0 0 1) substrates and (Yb,Nb):RbTiOPO4/RbTiOPO4 (0 0 1) epitaxial layers has been performed using fluorine chemistry. A maximum etch rate of 8.7 nm/min was obtained, and the deepest etch achieved was 3.5 mu 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 and 9-mm-long Y-splitter structures were designed and patterned in RbTiOPO4 substrates and (Yb,Nb):RbTiOPO4/RbTiOPO4 (0 0 1) 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 mu m has been measured and optical waveguiding at this wavelength has been demonstrated.