Abstract: A modalmetric fiber sensor comprising a multimode sensor fiber; a light source for launching light into the multimode sensor fiber to produce a multimode speckle pattern of light at an end of the multimode sensor fiber; a single mode fiber to receive light from the multimode speckle pattern; a detector connected to the single mode fiber to detect the received light from the speckle pattern; and a further multimode fiber disposed between the end of the sensor fiber and the single mode fiber such that the single mode fiber receives light from the speckle pattern by transmission through the further multimode fiber and the received light includes higher order modes regenerated in the further multimode fiber, wherein the further multimode fiber is overfilled with received light from the speckle pattern.

Abstract: A modalmetric fibre sensor comprises a multimode sensor fibre (26), a light source (14) for launching light into the multimode fibre (26) to produce a multimode speckle pattern of light at an end of the fibre (26), a single mode fibre (22) to receive light from the multimode speckle pattern and a detector (18) connected to the single mode fibre (22) to detect the received light from the multimode speckle pattern. A connector (33) connects the ends of the multimode fibre (26) and single mode fibre (22) with the end faces (31,32) of the two fibres disposed at an acute single to one another. The light from source (14) may be transmitted to the multimode fibre (26) through the single mode fibre (22) and the end of multimode fibre (26) remote from single mode fibre (22) may be mirrored to reflect light back along the multimode fibre to the single mode fibre which transmits the received light to the detector (18).

Abstract: A modalmetric fibre sensor comprises a multimode sensor fibre (26) and a light source (14) for launching light into the sensor fibre to produce a multimode speckle pattern at an end of the sensor fibre. A single mode fibre (22) receives light from the multimode speckle pattern for transmission to a detector (18). A further multimode fibre (41) is disposed between the sensor fibre (26) and the single mode fibre (22) so that the single mode fibre (22) receives light from the speckle pattern by transmission through the further multimode fibre (41) and the received light includes higher order modes regenerated in the further multimode fibre (41). The light source may be connected to the single mode fibre (22) so as to launch light through the single mode fibre into the multimode sensor fibre (26) via the further multimode fibre (41) and the remote end (28) of the sensor fibre (26) may be mirrored to reflect light back through the sensor fibre to produce the speckle pattern.

Abstract: A modalmetric fibre sensor comprises a multimode sensor fibre (26), a light source (14) for launching light into the multimode fibre (26) to produce a multimode speckle pattern of light at an end of the fibre (26), a single mode fibre (22) to receive light from the multimode speckle pattern and a detector (18) connected to the single mode fibre (22) to detect the received light from the multimode speckle pattern. A connector (33) connects the ends of the multimode fibre (26) and single mode fibre (22) with the end faces (31,32) of the two fibres disposed at an acute single to one another. The light from source (14) may be transmitted to the multimode fibre (26) through the single mode fibre (22) and the end of multimode fibre (26) remote from single mode fibre (22) may be mirrored to reflect light back along the multimode fibre to the single mode fibre which transmits the received light to the detector (18).