摘要:
An interferometric measurement system includes a spun optical fiber including multiple optical waveguides configured in the fiber. Interferometric detection circuitry detects measurement interferometric pattern data associated with each of the multiple optical waveguides when the optical fiber is placed into a bend. Data processing circuitry determines compensation parameters that compensate for variations between an optimal configuration of the multiple optical waveguides in the fiber and an actual configuration of multiple optical waveguides in the fiber. The compensation parameters are stored in memory for compensating subsequently-obtained measurement interferometric pattern data for the fiber. The compensation parameters are applied to the subsequently-obtained measurement interferometric pattern data in order to distinguish between axial strain, bend strain, and twist strain on the fiber and to accurately determine one or more strain values for the fiber corresponding to one or more of the axial strain, bend strain, or twist strain on the fiber.
摘要:
One or more mechanical parameters of a structure subjected to a force or condition are measured using distributed, optical fiber sensing technology. At least a curved portion an optical fiber having is attached to an object. A distributed, optically- based, strain sensing technique is used to determine strain information associated with multiple points along the curved portion of the fiber. The determined strain information is processed to generate one or more representations of one or more of the following: an expansion of the object, a thermal gradient associated with the object, or a stress- induced strain at multiple locations on the object corresponding to ones of the multiple points. An output is generated corresponding to the representation.
摘要:
An accurate measurement method and apparatus are disclosed for shape sensing with a multi-core fiber. A change in optical length is detected in ones of the cores in the multi-core fiber up to a point on the multi-core fiber. A location and/or a pointing direction are/is determined at the point on the multi-core fiber based on the detected changes in optical length. The accuracy of the determination is better than 0.5% of the optical length of the multi-core fiber up to the point on the multi-core fiber. In a preferred example embodiment, the determining includes determining a shape of at least a portion of the multi-core fiber based on the detected changes in optical length.
摘要:
An interferometric measurement system measures a parameter using at least one optical waveguide. A memory stores reference interferometric pattern data associated with a segment of the optical waveguide. Interferometric detection circuitry detects and stores measurement interferometric pattern data associated with the segment of the optical waveguide during a measurement operation. A spectral range of the reference interferometric pattern of the optical waveguide is greater than a spectral range of the measurement interferometric pattern of the optical waveguide. A processor shifts one or both of the measurement interferometric pattern data and the reference interferometric pattern data relative to the other to obtain a match and to use the match to measure the parameter. An example parameter is strain.
摘要:
The technology described here enables the use of an inexpensive laser to measure an interferometric response of an optical device under test (DUT) at reflection lengths significantly greater than the coherence length of the laser. This is particularly beneficial in practical interferometric applications where cost is a concern. In other words, inexpensive lasers having shorter coherence lengths may be used to achieve very high interferometric measurements at longer DUT reflection lengths. The technology also enables the use of such inexpensive lasers to measure Rayleigh scatter in commercial-grade, single-mode optical fiber.