Design of In-Situ Optical Fiber Sensor for Dissolved Oxygen and Chlorophyll-a in Ocean

In this study, an optical fiber sensor for detecting dissolved oxygen and algal chlorophyll-a content was described. Ethyl cellulose matrix doped with tris (2, 2'-bipyridine) ruthenium (II) (Ru(bpy)3 ²⁺ ) as a sensing material for dissolved oxygen. The light emitting diode of 450nm was used to excite chlorophyll-a which existed in algae and the sensing materials for dissolved oxygen. We apply fiber optic sensitive probes to measure different concentrations of dissolved oxygen and chlorophyll-a. The attenuation of the fluorescence intensity used to detect the dissolved oxygen concentration has a linear relationship with the increase of the dissolved oxygen concentration within the test range. In the range of testing, the relative fluorescence intensity for the probe of chlorophyll-a also linearly changes with the chlorophyll-a concentrations' increasing. The sensor can be used to monitor dissolved oxygen and chlorophyll-a in seawater.