CRITICAL MICELLE CONCENTRATION (CMC) SENSOR BASED ON POROUS SOL-GEL DOPED CLADDING U-SHAPED OPTICAL FIBER

摘要

In this paper, a sol-gel derived coating U-shaped optical fiber sensors for measurement of critical micelle concentration of surfactants has been studied. The doped sol-gel cladding fiber was used to construct an active cladding U-shaped optical fiber CMC measurement sensor. The porous sol-gel film was deposited a 1000μm core plastic clad silica fiber after removing the cladding of the fiber at the middle portion (6 cm) and bending in U-shaped design. CMC detection is based on an adsorption effect in sample solution of sodium dodecylbenzenesulfonate. The change in adsorption condition leads to an effective change in refractive index at the surrounding surface of the cladding (2). The effect of bending radius and particle size of sol-gel cladding of U-shape on sensor sensitivity was studied and compared. Three different types of particles size of sol-gel porous cladding were tested in our lab. Test results show that the sensitivity of the small particle size porous sol-gel cladding U-shaped optical fiber in sensing region is higher than that of large particle size sol-gel cladding. The sensitivity of the sensor also increases when the bending -radius of the U-shaped probes of the sensor decreases in all the three cases.