Combination measuring instrument of optical fiber Mach-Zehnder and Michelson interferometer array

Abstract

The invention provides a measuring instrument with an optical fiber Mach-Zehnder interferometer and optical fiber Michdson interferometer arrays, which comprises a broad-band light source 1, a photoelectric detector 2, a 3dB optical fiber 2 multiplied by 2 coupler 3, the optical fiber Mach-Zehnder interferometer, a transposed 3dB optical fiber 2 multiplied by 2 coupler 7, optical fiber Michdson interferometers arrays 8 and 8', and a single-mode connecting optical fiber 9, wherein, the optical fiber Mach-Zehnder interferometer consists of an attenuator 4, a self-focusing lens 5, an axicon lens6 with total reflection angle, and the connecting optical fiber 9. The measuring instrument with the optical fiber Mach-Zehnder interferometer and the optical fiber Michdson interferometer arrays utilizes a technique that measures strain and temperature at the same time, realizes the temperature compensation technique and the array arrangement of optical fiber sensors, realizes absolute measurement under the situation that the multiple sensors are not interfered by each other, lowers the cost of single-point measurement and ensures real-time measurement; furthermore, the measuring instrument has simple techniques and easy implementation, and as standard optical fiber communication elements are adopted as the optical fiber materials and devices, the measuring instrument has low cost, easy acquisition of the optical fiber materials and devices and easy popularization.

Description

(1) Technical field [0001] The invention relates to a measuring device, in particular to a measuring instrument of an optical fiber interferometer array based on the principle of white light interference. (2) Background technology [0002] The research and development of fiber optic interferometry systems with different types of low-coherence light sources (broad-spectrum light sources, narrow-spectrum LEDs, SLEDs and ASEs, multimode laser diodes, etc.) has become a very active technical field. As a branch of fiber-optic interferometry, low-coherence source measurement systems have demonstrated many advantages over other fiber-optic interferometry systems. The biggest feature is that it can perform absolute measurement on the measurand. In addition, it also has high resolution and wide dynamic range. Because the low-coherence light source and multimode fiber used in the system are cheap, the system cost is low. White light interferometers are widely used in the measurement...

AI Technical Summary

Problems solved by technology

As disclosed in [SANTOS JL, JACKSON D A. Coherence sensing of time-addressed optical-fiber sensors illuminated by a multimode laser diode, Appl. Opti., 30:5068-5077, 1991], the time division multiplexing technology (TDM) is The multiplexing technology uses the delay effect of optical fiber to address the light wave. This method has complex structure, limited number of multiplexing, small measurement range and low measurement accuracy; in addition, [LIU T, FERNANDO G F.A frequency division multiplexed low-finesse fiber OpticalFabry-Perot sensor system for strain and displacement measurements, Review of Scientific instruments, 71 (3), 1275-1278, 2000] disclosed frequency division multiplexing technology (FDM), using a spectrum analyzer to directly measure a plurality of different cavity lengths The spectral superposition results of the Fabry-Perot interferometer output, this method is limited by the cavity length and cavity length difference, the number of multiplexing of the interferometer is very limited, only a few

And [LiboYuan, Qingbin Li, Yijun Liang, Fiber optic 2-D sensor for measuring the strain inside the concrete specimen. Sensors and Actuators A, 94 (2001) 25-31] disclosed space division multiplexing technology (SDM), through The plane reflector in the reference arm performs spatial continuous optical path scanning, which can realize the demodulation and interrogation of multiple sensors, so that two-dimensional strain measurement can be easily realized. This method has a simple structure and high measurement accuracy, but because only A reference plane makes the scanning range of the plane mirror need to be large, and when the system contains multiple sensors, due to the attenuation of the reflected signal intensity of the sensing arm, the contrast of the interference signal will be poor, and the white light interference signal is very weak, so the interference The multiplexing number of the instrument is only a few

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