A Fiber Optic Pickup and Sensing System Based on the Principle of Interference Filtering

Abstract

The invention provides an optical fiber vibration pickup based on an interference filtering principle. The optical fiber vibration pickup is characterized by comprising a pedestal, a cantilever beam,a mass block, an optical filter and collimators; wherein one end of the cantilever beam in the horizontal direction is fixed on the base, and the other end of the cantilever beam is connected with themass block to form a mass-vibration system which can only vibrate in the vertical plane, a central hole is formed in the cantilever beam, the optical filter is arranged in the central hole, and a light input end and an output end are arranged on the upper and lower sides of the optical filter respectively, collimators are arranged between the optical filter and the input end and between the optical filter and the output end, the optical filter is coaxial with the collimators, and the collimator is fixed on the base through a mounting bracket; and the optical input end and the output end are all optical fibers. The contradiction between the sensitivity and the frequency response range is well solved, and the sensing performance of the low-frequency vibration pickup is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of engineering vibration measurement and optical fiber sensing, and in particular relates to an optical fiber vibration pickup and a sensing system based on the principle of interference filtering. Background technique [0002] In engineering vibration measurement, the sensors that pick up vibration signals are mainly piezoelectric and electromagnetic vibration pickers. However, in some specific measurement occasions, such as high voltage, strong magnetic field, flammable and explosive occasions, the application of the above-mentioned sensors is limited. For this reason, fiber optic pickups are born. The existing fiber optic pickups are based on the tuning parameters There are various sensors such as light intensity type, wavelength type, polarization type, and phase type. Among them, the wavelength type fiber optic pickup not only has the characteristics of anti-electromagnetic interference and intrinsic sa...

AI Technical Summary

Problems solved by technology

However, there is a problem in the performance of this structure fiber grating vibration pickup: that is, the sensitivity and the working frequency band are usually contradictory

Under the premise of meeting the measurement accuracy requirements, the frequency response bandwidth of the sensor is too narrow to meet the application requirements of engineering vibration measurement; in addition, the Chinese patent No. ZL201310749018.7 discloses "a fiber grating vibration sensor for liquid media ", this patent adopts an improved cantilever beam (L beam) structure, and adopts a double grating design, which better solves the problem of temperature compensation and significantly improves the detection sensitivity of the sensor

However, in order to improve the long-term durability of fiber gratings, the frequency response must be sacrificed to reduce the vibration amplitude

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