Planar optical waveguides prepared in GIL49 and BK7 glass substrates by K+-Na+ ion exchange with the electric field assistance

This report focuses on research into waveguides prepared by K+-Na+ ion exch ange with the help of an electric field, and the subsequent comparison with waveguides prepared by pure thermal ion exchange. The goals of this work w ere to determine the characteristics of and to address the technological pr oblems associated with waveguides prepared in two types of highly pure opti cal glass: special soda-lime silica GIL49 glass produced from pure raw mate rials and commercially prepared borosilicate BK7 glass. An appropriate chem ical mixture, KNO3:Ca(NO3)(2) in the molar ratio of 41:59, was used as the source of potassium ions. Experiments were conducted at temperatures betwee n 250 and 410 degrees C, and electric field values between 0 and 150 V/mm. The number of modes, depth, profile, and the change in refractive index (bn ) were measured for samples from each type of glass under various technolog ical conditions. All of these parameters can be controlled accurately and r epeatedly by the electric field. These experiments have also shown that a p articular advantage of these types of pure glass is the low waveguide optic al losses (0.1 to 0.2 dB/cm) attainable.