||Optical fiber created a new era of telecommunications transmission. Associated with sophisticated quality of the optical and optoelectronic components, the fiber optic sensors manufactured by combining optical and optoelectronic components have been widely used in environmental and pollution monitoring, defense, laboratory analysis, clinical diagnosis and other medical applications. Every specific application of the fiber optic sensors has its own individual needs and concerns, such as sensitivity, accuracy, selectivity, lifetime and cost. Recently, fiber optic has been used to measure various parameters of biomedicine and biotechnology.|
In this thesis, basing on the production technology of the evanescent wave fiber optic sensors we present a pH sensor with smaller volume of specimen. The specifications of the fiber optic we used are multimode plastic optical fiber, Model CK-40 Eska, 1mm diameter. And the material of fiber cladding is fluorinated polymers, fiber core is PMMA. Retaining the fiber cladding, drilled a 0.2mm round hole that the fiber cladding and the fiber core are penetrating through. We defined this as core-defect. Applying the sol-gel method and pH indicator constructed pH sensing materials. This sensing material is injected into the hole mentioned above and built a bundle sensing area itself. The core-defect pH sensors that we produced require a specimen amount 50 ~ 150μl, its response time is 40 seconds and the sensing range is pH4 to pH10.