title: Observation of intensity-induced nonreciprocity in a fiber-optic gyroscope.
abstract: Nonreciprocal phase shift has been predicted and observed in a fiber-optic gyroscope based on a Sagnac interferometer when the intensities of the counterpropagating beams are unequal. The magnitude of this intensity-induced phase shift is 1.4 rad/W power difference. At 1-microW power difference, this is equivalent to a rotation rate of 0.2 degrees /h in our 200-m-long fiber with a core radius of 2.25 microm that is wound around a spool of 19-cm diameter. The data are consistent with theoretical predictions based on four-wave mixing in the quartz fiber.
authors.forename: S
authors.initials: S
authors.lastname: Ezekiel
authors.forename: J L
authors.initials: JL
authors.lastname: Davis
authors.forename: R W
authors.initials: RW
authors.lastname: Hellwarth