Methods and apparatuses for obtaining information, such as location and/or identification information, regarding sensors in optical paths such as optical fibers. One embodiment provides a method for identifying a location of a tag in an optical path. The tag is (1) adapted for producing a response to an optical signal propagating along the optical path; and (2) responsive to a variation of a physical parameter to vary the response to the optical signal. The method comprises causing a variation of the physical parameter and identifying the location of the tag at least in part by observing the response of the tag to the optical signal. The tag may be associated with a sensor such that a location of the sensor may be derived based on the location of the tag.