Microring embedded hollow polymer optical fiber for refractive index sensing

Abstract We report an active refractive index sensor based on interferential modulated whispering gallery mode lasing in a microring embedded hollow polymer optical fiber. Transverse optical pumping leads to strongly modulated and directional lasing modes from the fiber. The lasing modes with a quality factor of 1.3 × 10 4 were obtained from the fiber, when it was immersed in water. The observed quality factor of microring embedded hollow polymer immersed in water fiber is higher than that of a dye doped hollow polymer fiber. In comparison with the surface emitting dye doped hollow fiber, microring embedded hollow polymer optical fiber can provide selective mode and confined lasing in the fiber end. The lasing modes from the microring embedded hollow polymer fiber sensor show a red shift with the increase in liquid refractive index yielding a refractive index sensitivity of 188 nm/RIU which is higher than that of dye doped hollow polymer based refractive index sensor.