Fabrication of Y-splitters and Mach¿Zehnder structures on (Yb,Nb):RbTiOPO4/RbTiOPO4 epitaxial layers by reactive ion etching.

Identifier:  PC:2847

Handle: https://hdl.handle.net/20.500.11797/PC2847

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

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.