A force measuring device generally comprising a hollow, three-dimensional container defining interiorly thereof at least one chamber is disclosed. The device includes at least a pair of optical fiber coils with the length of the optical fiber on each of the coils being substantially equal. The pair of coils are mounted on opposite sides of a wall of the hollow container and there are means within the container normally exerting a force on the coil mounted within the container. The system also includes an optical interferometer having a pair of legs with means connecting each of the pair of coils in a leg of the interferometer. Radiant energy emitting means are provided for directing radiant energy into the legs of the interferometer and through the pair of coils and radiant energy detecting means are connected to the interferometer.