In this paper, the fabrication of optical planar waveguide in PTR glass by proton implantation is reported for the first time to our knowledge. The planar waveguide with a width of approximately 3.4 μm was generated under the condition of 400 keV H+ ion implantation with a dose of 8.0 × 1016 ions cm−2 at room temperature. The formation mechanism of PTR glass waveguide was illustrated with the aid of the SRIM program. The optical characteristics of the PTR waveguide, such as refractive index profile and near-field intensity distribution, were investigated in detail. The fabricated PTR waveguide presents a structure of both index-well and optical barrier according to the reconstructed refractive index profile. The finite-difference beam propagation method was carried out to simulate guiding modal distribution. Besides, in order to study the thermal stability of the H+-implanted PTR waveguide, annealing treatment was conducted at different temperatures. © 2020 Elsevier GmbH