Channel waveguides and Mach-Zehnder structures on RbTiOPO₄ by Cs⁺ ion exchange

• Main Authors: Butt, M.A (Author), Pujol, M.C (Author), Solé, R. (Author), Ródenas, A. (Author), Lifante, G. (Author), Wilkinson, J.S (Author), Aguiló, M. (Author), Díaz, F. (Author)
• Format: Article
• Language: English
• Published: 2015-04-22.
• Subjects: Article
• Online Access: Get fulltext

Cs⁺ ion exchange in RbTiOPO₄ and (Yb,Nb):RTP/RTP(001) has been used to locally increase the refractive indices for waveguide circuit fabrication. Ti masks were fabricated on RTP samples by conventional photolithography. Cs⁺ exchange was done using a CsNO₃ melt at 698 K during 2 h. Elemental analysis confirms an Cs⁺ profile with a variable depth. Apparently the Cs⁺ exchange is disfavored in the doped epitaxial sample. The refractive index variation is higher for nz than for nx,y. Near-field images of the guided modes at 633, 1064 and 1520 nm were recorded. The optical characterization shows propagation losses of 5 dB/cm at 1520 nm.