Optical Phase Refractometer Based on Post-Processed Interferometric Tip Sensors

An ultra-high sensitive strain sensor is proposed. The sensing head, based on the post-processing of a fiber Bragg grating, is used to perform passive and active strain measurements. Both wavelength and full width half maximum dependences with the applied strain are studied for the passive sensor, where maximum sensitivities of 104.1 pm/µepsilon and 61.6 pm/µepsilon are respectively obtained. When combining the high performance of this sensor with a ring laser cavity configuration, the Bragg grating will act as a filter and high resolution measurements can be performed. With the proposed sensor, a resolution of 700 nepsilon is achieved.