A novel core-offset hollow core photonic bandgap fiber (HCPBF) based intermodal interferometer is presented. It is fabricated by splicing a section of HCPBF between two single mode fibers with a slight core offset at one splice joint. The fabrication process only involves splicing and cleaving. Its applications for strain and temperature measurements are also demonstrated. Its strain and temperature sensitivities are -1.17 pm/με and 6.66 pm/°C, respectively.