Temperature compensation accelerometer based on polarization maintaining optical fiber double-arm heteroaxial interferometer

Abstract

The invention provides a temperature compensation accelerometer based on a polarization maintaining optical fiber double-arm heteroaxial interferometer. An all-polarization-maintaining optical fiber interferometer is adopted as a sensing light path, a sensing arm of the interferometer is welded in a staggered-axis mode to achieve double-arm different-axis interference, and optical fibers of the two sensing arms of the interferometer are sensitive to strain and temperature at the same time; a polarization maintaining optical fiber interferometer and a push-pull type mechanical vibration pickupstructure are compounded, acceleration is converted into optical fiber strain through a vibration pickup structure, and two sets of sensing systems which have different responses to temperature and acceleration at the same time are constructed in the same sensor. In the sensor, the temperature response and the acceleration response of the two sensing systems are the temperature effect difference value and the strain effect sum of the two sensing arms respectively, and under the balance interferometer, the temperature response coefficients of the two sensing systems are equal in numerical valueand opposite in symbol, and the acceleration response symbols are the same. Phase responses of the two sets of sensing systems are added, the strain response is increased while the temperature response is eliminated, and the acceleration sensitivity of the sensor is improved.

Description

technical field [0001] The design of the invention belongs to the technical field of optical fiber sensing, and in particular relates to a temperature compensation accelerometer based on a polarization-maintaining optical fiber dual-arm off-axis interferometer. Background technique [0002] Acceleration is an important physical quantity that describes the state of motion of an object, and the instrument used to measure acceleration is called an accelerometer, which is an important measurement component for controlling detection equipment and guiding navigation. Compared with traditional accelerometers, fiber optic accelerometers have the advantages of small size, light weight, high sensitivity, large dynamic range, anti-electromagnetic interference, and can work in harsh environments, so they are widely used. Due to the temperature-sensitive characteristics of fiber optic materials, fiber optic sensors are very sensitive to temperature changes, so this type of sensor has ser...

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Problems solved by technology

In 2015, Bian Jicheng and others of China Institute of Metrology proposed a sensor for simultaneous measurement of temperature and strain based on spherical and thin-core optical fibers (CN201520488312.1), using special optical fibers to make the cladding mode and core mode form a Mach-Zehnder interferometer to achieve The function of measuring temperature and strain at the same time eliminates the crosstalk between the two; but the cost of special optical fibers is high, and is limited by the fiber drawing technology, and the unstable quality of some special optical fibers leads to inconsistent performance of the sensor

However, the biaxial parameters of polarization-maintaining fibers are very close, so the intrinsic response matrix approximates an ill-conditioned matrix (that is, the coefficients in the matrix are very close to cause a small change in the coefficients will cause a large deviation in the calculation results), resulting in the separation results of temperature and strain. Large crosstalk terms, difficult to achieve clean separation

Invention patent Unbalanced polarization-maintaining optical fiber double interferometer temperature and strain simultaneous measurement method and device Although the ideal matrix can be obtained through matrix transformation, the non-ideality of the intrinsic response matrix cannot be changed, so this method is also difficult to achieve high-precision temperature compensation

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