High spatial resolution fiber optic distributed force sensing with synthesis of optical coherence function

摘要

Arbitrary characteristics of optical interference have been realized, in our group, by Synthesis of Optical Coherence Function(SOCF) with electrical control and without mechanical scanning. Various applications for optical sensing have been developed by SOCF. Delta function like optical coherence function with higher spatial resolution and higher dynamic range have been achieved by using a broadband tunable super-structure-grating distributed Bragg reflector laser diode (SSG-DBR-LD). This time, we improve driving circuit and frequency calibration of the SSG-DBR-LD to achieve a 5THz tunable band width. We apply the characteristics to distributed fiber optic force sensing using polarization maintaining fiber (PMF) as a sensing head. Its principle is polarisation mode coupling by the force applied to the fiber. In the experiment, we improve the spatial resolution more than one digit compared with the previous data, and realize 20cm. This technique can be used as a nerve system for smart materials and structures.