Phase Measurement of Optical Fiber via Weak-Value Amplification

A precision phase detection scheme employing a weak-value amplification (WVA) technique is proposed and demonstrated. With a minimum detectable phase change of
$\sim \!10^{-5}$
rad, the present system rivals similar free-space schemes using bulk optical components only. The new setup is tested in a simple hydro-pressure detection experiment, with a short segment of fiber under water, showing a remarkable responsivity to small pressure changes.