Application of the channel optical waveguide prepared by ion exchange method to the preparation and characterization of an optical oxygen gas sensor

An optical oxygen gas sensor, based on the principle of luminescence quenching by oxygen, was fabricated using a planar optical waveguide formed by ion exchanging method and its sensing performances were studied. Ion exchanging process was performed by substituting Ag+ for Na+ by immersing a patterned, 8 μm in size, phosphate glass into a jig for 20 min at 250 °C. Platinum octaethylporphyrin (PtOEP), selected as an oxygen quenchable material, was partially coated on the planar optical waveguide coupled to a single mode optical fiber, and then it was placed in a sensing cell. The sensing performances of the sensor were studied by measuring the photoluminescence intensity of PtOEP excited by a green laser beam (532 nm). It was observed that the photoluminescence intensity decreases as the oxygen concentration increases. The Stern-Volmer plot of the sensor shows linearity in the oxygen concentration range between 0 and 20%. Response time and recovery time were measured to be 100 and 80 s, respectively. These results show the potential for developing an optical oxygen gas sensor using a planar optical waveguide.