Investigation of Carbon ion-implanted waveguides in tungsten bronze (Ca0.28Ba0.72)0.25(Sr0.6Ba0.4)0.75Nb2O6 single crystal

• Fabrication of planar waveguides in CSBN25 crystal by MeV C ion implantation at low fluence.
• The extraordinary index has a small positive change in the surface region after the implantation.
• The relation between index profile parameters and C+ ion energy loss were considered.

Planar optical waveguides were fabricated in (Ca0.28Ba0.72)0.25(Sr0.6Ba0.4)0.75Nb2O6 (CSBN25) crystal by 6.0-MeV C+ ion implantation with fluences of 2, 4 and 6 × 1014 ions/cm2 at room temperature. The mode parameters, refractive indices profiles are measured and the refractive indices behavior in the waveguide region is discussed. The shape of nuclear energy loss distribution of the C+ implantation was similar to those of the waveguide refractive index profiles, which means an inherent relationship between the waveguide formation and the energetic energy deposition. The extraordinary refractive index has a small positive change in the surface region after the implantation.