KTiOPO4 double barrier optical waveguides produced by Rb+-K+ ion exchange and subsequent He+-ion irradiation

We report on the fabrication and characterization of KTiOPO4 optical waveguides formed by Rb+-K+ ion exchange in high-purity RbNO3 melt at 340 degrees C for 90 min and subsequent He+-ion irradiation at energy of 500 keV and fluence of 3 x 10(16) ions/cm(2). The irradiation of KTiOPO4 crystals with He+ ions was simulated using the stopping range of ions in matter (SRIM'2006) software. The dark mode spectra of the samples were measured with the prism coupling method. The reconstructed refractive index profiles of the planar waveguide show a barrier in the middle of the guiding region, and a refractive index enhancement region on each side of the barrier, indicating the formation of a double waveguide. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)