Strain measurement pick=up for weighing appts. - operates on interferometer principle, and amplifies change in optical guide length by multiple reflections of beam

摘要

Strain is measured with an interferometer whose measurement beam (4) is guided into an elastic light-guide (14) subject to changes of shape corresp. to the length or distance variation to be measured. The effect is amplified by multiple reflections of the beam (4) between two parallel mirrors (10,11) before and during its return (15) to the interferometer. The light-guide (14) may be a thin silicon chip similar to that (16) in which the interferometer is formed. ADVANTAGE - Signal-to-noise ratio of interferometer is good, with intensity of measurement beam largely independent of its length.