Quantum nondemolition measurements in an optical-fiber ring resonator

A quantum nondemolition (QND) measurement scheme utilizing a Kerr medium enclosed in a resonant cavity is described and analyzed theoretically. The theory demonstrates that the conditions for QND can be met in such a device. An experimental realization in the form of an optical-fiber ring resonator has been constructed and initial experimental results are presented. © 1988 The American Physical Society.