MICROPHONE WITH INTERFEROMETRIC DETECTION OF ACOUSTIC PRESSURE

摘要

The microphone, by means of which acoustic signals whose spectrum is above 20Hz, may be measured, comprises a reference space exempt from this signal. It further comprises a monomode light source (10) and an optical interferometer with a reference arm extending across the reference space and an active arm whose length (L1) is altered by the acoustic signal at a value approximately equal to that (L2) of the reference arm; also provided are means for measuring the variations of the active arm's optic path caused by the acoustic signal.