Channel waveguides and Mach-Zehnder structures on RbTiOPO_4 by Cs^+ ion exchange

Abstract
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 n(z) than for n(x,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. (C) 2015 Optical Society of America
Funding Information
  • Spanish Government (MAT2011-29255-C02-02, TEC2014-55948-R, MAT2013-47395-C4-4-R/1-R)
  • Catalan Authority (2014SGR1358)
  • icrea
  • Catalan Government
  • FI-DGR fellowship (2012FI-B 00192)