Abstract: An optical fiber device for measuring strain has a first portion which generates a first signal, and a second portion which generates a second signal and is located proximate the first portion. The first and second portions are made of different component types of optical fibers. A fiber carries a superposed signal to readout interferometers which recover individual strain signals from the superposed signal. The individual strain signals are processed to obtain strain measurements in two or more orthogonal directions in the host material. The optical fiber device may also include a third portion which generates a third signal and is located proximate the second portion opposite the first portion.