Planar optical waveguides in Bi4Ge3O12 crystal fabricated by swift heavy-ion irradiation

We report on the fabrication of the planar waveguides in Bi4Ge3O12 crystal by using 17 MeV C5+ or O5+ ions at a fluence of 2×10(14) ions/cm2. The reconstructed refractive index profiles of the waveguides produced by either C5+ or O5+ irradiation are the "well" + "barrier" pattern distribution. The two-dimensional modal profiles of the planar waveguides, measured by using the end-coupling arrangement, are in good agreement with the simulated modal distributions. After thermal annealing treatment at 260 °C for 30 min, the propagation loss for C5+ and O5+ irradiated waveguides could be reduced down to ~1.1 and ~4.8 dB/cm, respectively, which exhibit acceptable guiding qualities for potential applications in integrated optics.