Patent ID: 8358882
Filing Date: 2013-01-22
Classification: G01D,G02B,G08B

Abstract:
1. A modalmetric fibre sensor comprising a multimode sensor fibre; a light source for launching light into the multimode sensor fibre to produce a multimode speckle pattern of light at an end of said multimode sensor fibre which speckle pattern is changed by vibration or perturbation of the multi-mode sensor fibre; a single mode fibre of smaller core diameter than the multi-mode sensor fibre having an end connected to said end of the multimode sensor fibre to receive light from a central part of the multimode speckle pattern; and a detector connected to the single mode fibre to detect the received light from the multimode speckle pattern; wherein the end faces of said ends of the multimode sensor fibre and the single mode fibre are disposed at an acute angle to one another whereby said end of the single mode fibre receives an asymmetrically stretched central part of the speckle pattern in which the changes in that pattern due to vibration or perturbation of the multi-mode sensor fibre are exaggerated so as to enhance sensitivity of the modalmetric fibre sensor.