Mid-infrared ridge waveguides fabricated in CaF2 crystal by the technique of O5+ ion irradiation

The fabrication of ridge waveguides in calcium fluoride (CaF2) crystal working at the mid-infrared wavelength was studied. First, the planar waveguide was fabricated by using O5+ ion irradiation, and then the ridge waveguide structure was manufactured by precise diamond blade dicing. The propagation loss was measured by end-face coupling arrangement, and then annealing treatment was implemented to optimize the waveguide performance, and the propagation loss was finally reduced to 0.5 dB/cm. We measured the Raman spectra of the waveguide and substrate to observe the damage to the material lattice caused by O5+ ion irradiation technology. (C) 2021 Optical Society of America