Totally six polarization-maintaining optical fibers having the same beat length are arranged at both ends of a single-mode optical fiber and both ends of a single-mode optical fiber coil, respectively. An angle between a principal axis of polarization in a...

A method for measuring the tread thickness from the radially outermost belt surface within a tire to the tread surface accurately by ultrasonic measurement whatever the type of belt material is. The method includes the steps of measuring a profile of the t...

A thickness measurement apparatus and method thereof being possible to measure an object to be inspected with required sensitivity stability and accuracy is provided. The thickness measurement apparatus 1 includes: an ultrasonic wave transmission/reception...