摘要:
A multi-mode fibre optic sensor for optically sensing a physical perturbation includes a multi-mode optical fibre segment (14) which accepts coherent monochromatic radiation from a suitable source (12). As the radiation is propagated in the fibre (14), the various modes form a complex interference pattern which changes in response to a physical perturbation of the fibre. A detector (16) provides an output signal to a signal processor (18) which analyzes the signal as a function of the change in intensity to provide an information signal functionally related to the perturbation.
摘要:
A joined structure (10) is provided with a laminate sheet (12A), a laminate sheet (12B), an adhesive (14) that joins the laminate sheet (12A) and the laminate sheet (12b), and an optical fiber (16) that is sandwiched between the laminate sheet (12A) and the laminate sheet (12B). As a result of the cross-sectional shape of the optical fiber (16) changing to an elliptical shape only when pressure is applied to the optical fiber (16) from a predetermined direction, birefringence that changes to a shape having a plurality of peaks (2, for example) occurs in the optical spectrum. The optical fiber (16) can be used as a sensor for detecting the joined state of the laminate layer (12A) and the laminate layer (12B) using the birefringence. As a result, it is possible to determine whether the members of the joined structure (10) are suitable joined.
摘要:
An optical sensor (50) employing an optical wave-guide (10) is disclosed. The sensor (50) senses stress placed on the wave-guide (10) due to changes in the external environment. Light is launched into a restricted group of core modes of a fiber wave-guide and is redistributed in the fiber due to changes in the external environment. These changes can be detected and may be used to interpret the amount of stress on the fiber (10).
摘要:
Fiber optic sensors based on multicore optical fibers that are intended for use in harsh environment sensing. This multicore fiber comprises an arrangement of optically coupled cores in a silica background. Sensors are fabricated by splicing a section of multicore fiber between two single mode fibers. This multicore fiber sensor is simple and repeatable to fabricate and multiple sensors can be multiplexed in a chain. These fiber optic sensors are intended for a broad set of sensing applications including temperature, pressure, strain, bending, acoustic vibrations, mechanical vibrations, or combinations thereof.
摘要:
The present invention provides a photosensor that uses a phase modulation technique for optical detection and conducts a highly accurate measurement. The photosensor uses a phase change difference of light propagated through a polarization preserving fiber with respect to tensile stress and employs proper polarization preserving fibers for a phase modulator 10, light-transmitting polarization preserving fiber 23, and coil-shaped polarization preserving fiber 30, to achieve a highly accurate measurement.
摘要:
According to the present invention there is provided an optical transducer adapted to detect external mechanical actions acting on said transducer, said transducer comprising at least one sensing optical path (5) adapted to transmit at least one sensing optical signal (b') and to emit at least one sensing output electrical signal (d) along with at least one reference path (4) adapted to emit at least one output electrical reference signal (e). Moreover, at least one portion (5') of said at least one optical path (5) is adapted to be exposed to external mechanical actions, so that the transmission of said sensing optical signal (b') through said sensing optical path can be modified as a result of said mechanical actions, so that a phase shift between said sensing electrical signal (d) and said reference electrical signal (e) is generated. Furthermore, said at least one reference path (4) comprises phase shifting means (11) adapted to maintain the phase shift between said at least one output sensing electrical signal (d) and said at least one output reference electrical signal (e) at a constant value in absence of any mechanical action exerted on said at least one sensing optical path (5), resulting in the working point of the transducer being kept within a range centered o a predefined phase shift, thus allowing to improve the sensitivity pf the transducer.
摘要:
Faseroptische Sensoren werden in Reflexions- oder Transmissionsbetrieb in fast allen Bereichen der Meßtechnik eingesetzt, u. a. zur Überwachung von industriellen Anlagen, in der medizinischen Diagnostik sowie in der Luft- und Raumfahrt. Dabei werden die Wirkungen von mechanischen, elektrischen, magnetischen, akustischen, thermischen und chemischen Signalen ausgewertet. Um eine einfachere Signalauswertung zu ermöglichen, wird Laserlicht aus einer Lichtquelle (1) in eine Zuleitungslichtfaser (2) parallel zu einer von deren beiden Hauptachsen eingekoppelt. In einer 1. Spleißstelle (3) wir das Licht in eine 1. Referenzlichtfaser (4) eingeleitet, deren Hauptachsen um 45° gegenüber denen der Zuleitungslichtfaser (2) gedreht sind. In einer 2. Spleißstelle (5) gelangt das Licht in eine zur 1. Referenzlichtfaser (4) gleich lange 2. Referenzlichtfaser (6), die mit ihren Hauptachsen um 90° bezüglich der 1. Referenzlichtfaser (4) gedreht ist. An einer 3. Spleißstelle (7) wird das Licht in eine niedrigdoppelbrechende Lichtfaser (8) eingekoppelt, welche erst eine λ/4-Lichtleiterschleife (9) und danach einen optischen Sensor (10) bildet. Mittels eines Phasenmodulators (M) in Verbindung mit der 1. Referenzlichtfaser (4) kann die Phasenverschiebung des Lichtes statisch oder dynamisch beeinflußt werden.