title: Modal interferometer for in situ measurements of induced core index change in optical fibers.
abstract: A simple interferometer based on modal interference is described. Without compromising interferometer stability it is possible to measure index changes of less than 1 x 10(-6).
authors.forename: J
authors.initials: J
authors.lastname: Canning
authors.forename: A L
authors.initials: AL
authors.lastname: Carter