Methods, structures, devices and systems are disclosed for implementing a fiber optic force sensing transducer. In one aspect, an exemplary fiber optic force sensing transducer device includes an optical fiber coated by at least one layer of a polyelectrolyte material that utilizes the movement of optical structures coupled to the external polyelectrolyte layer in an evanescent field produced by the optical fiber to detect forces imposing on the fiber. In one aspect, an optical sensing device includes an optical waveguide that internally guides light, one or more layers formed outside the optical waveguide within an evanescent field of the guided light in the optical waveguide, and one or more optical structures coupled to the one or more layers in the evanescent field to emit light based on interaction with the evanescent field to indicate a position of an optical structure relative to an external surface of the optical waveguide.