MAGNETIC FIELD FIBER-OPTIC TRANSDUCER Russian patent published in 2005 - IPC

FIELD: magnetic measurement technology; flaw inspection.

SUBSTANCE: transducer has radiation source, unit for introducing radiation into multimode optical fiber, photoreceiver, both disposed one after another on the path of radiation and two or more films made of magneto-optic material and disposed at different parts of fiber. Magneto-optic material has periodic domain structure. Surface of any magneto-optic film is perpendicular to axis of fiber. Mode filter intended for selection of axial mode in fiber is disposed between unit for introducing radiation into optical fiber and first film of magneto-optic material. Mode demultiplexer is disposed at the point where radiation comes from the fiber. Photoreceiver is made to have number of photosensitive areas being equal to number of magneto-optic films. Period of domain structure of adjacent films changes times, where N is total number of films in the device. Minimal period of domain structure in the films made of magneto-optic material relates to numerical aperture of fiber as λ/d<=NA, where λ is radiation wavelength, d is period of domain structure, NA is numerical aperture of optical fiber.

EFFECT: improved precision of measurement.

1 dwg