He+ implantation for waveguide fabrication in KTP and Rb : KTP

Z-cut flux grown KTP single crystals were implanted at room temperature wit h total He ion fluences ranging from 3.2 x 10(15) to 3.2 x 10(16) cm(-2). T he energy was varied between 250 keV and 5 MeV, All samples were furnace an nealed at 250 degrees C. 300 degrees C and 350 degrees C in normal atmosphe re. By means of m-line spectroscopy the guided mode spectra as well as the refractive index profiles were determined. A dose-dependent decrease of the refractive index at the depth of maximum nuclear energy deposition down to values around Delta n = -0.14 was observed. The thickness of the near surf ace waveguides ranged from 0.6 to 23 mu m and correlates well with the dept h distribution of the nuclear energy deposition. Only waveguides formed wit h ion fluences above 1.3x10(16) cm(-2) remained stable after annealing, An equivalent behaviour of the value and depth distribution of the refractive index is found for Rb-exchanged KTP after implantation, The formation of bu ried optical channel waveguides by He implantation into Rb-exchanged KTP wa s demonstrated for the first time, The nearfield pattern and the transmitta nce of the waveguides were measured. (C) 1999 Elsevier Science B.V. All rig hts reserved.