An optical contact force sensor for tactile sensing based on specklegram detection from concatenated multimode fibers

•Specklegrams from different concatenated fibers are compared and analyzed.•Sensor head with MMF housed in enables conversion of force into fiber deformation.•Changes in the ZNCC of fiber specklegrams characterize the fiber deformation.•Concatenated fiber enables good force sensing and is insensitive to disturbance.•Specklegram detection from concatenated fiber applied to tactile sensing is shown.