Graphene Oxide Coated PCF Interferometer for Enhanced Strain Sensitivity

We propose a graphene oxide (GO) coated photonic crystal fiber (PCF) based modal interferometer for strain and temperature sensing. This Mach-Zehnder interferometer based probe has been fabricated by splicing PCF with single mode fiber (SMF) and creating a short collapsed region at one of the SMF-PCF junction and a long collapsed region at the other splicing junction. The PCF along with the collapsed regions is coated with GO prepared by Hummers method. The short collapsed region has been used to excite core and cladding modes in PCF while the long collapsed region is used for better interaction of core and cladding modes with GO. The change in refractive index of GO has been utilized to monitor strain. The uncoated probe shows a strain sensitivity of 1.6 pm/μe while the GO coated probe shows a strain sensitivity of 3.1 pm/μe, thereby enhancing the strain sensitivity by 93%. Further, the probe shows a temperature sensitivity of 14 pm/°C.