Measuring device for interferential sensor arm length difference

Abstract

The invention discloses a measuring device for an interferential sensor arm length difference. The measuring device comprises a broadband light source, a Mach-Zehnder intensity modulator, a microwave frequency sweeping source, a power divider, a direct-current stabilized power supply, a high-speed photoelectric detector, a radio-frequency amplifier, a phase shifter, a frequency mixer, a low-pass filter, an AD sampler and a measuring processer. The measuring device breaks through a thinking mode of measurement in a pure light domain, a microwave signal is led in, and a signal of the arm length difference is modulated on a light load microwave phase by the aid of an original light path structure of a sensor without damaging the sensor, so that the arm length difference is measured by demodulating the microwave phase. The measuring device mainly has the advantages that the measuring device is low in implementation cost, wide in measuring range, high in accuracy and high in speed, does not need to be supported by a special instrument and can fully automatically measure, manual adjustment is omitted, and a measuring result can be outputted only by connecting a measured sensor on the measuring device.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensor performance measurement, and in particular relates to a measuring device for interferometric sensor arm length difference. Background technique [0002] Interferometric sensors are sensing devices that have emerged in the past 20 years, and can be directly used to monitor physical quantities such as underwater sound, current, and magnetic field. This type of sensor has the characteristics of high sensitivity, high precision, fast measurement speed and strong anti-interference ability. The common structures of interferometric sensors are optical fiber Michelson interferometers (such as figure 1 shown), Mach-Zehnder interferometer (such as figure 2 shown), etc.; common optical fiber hydrophones, optical fiber magnetic field meters, etc. are all sensors of this structure. Its main working principle: usually the interferometric sensor has two fiber arms with different lengths. The mea...

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Problems solved by technology

[0004] The common feature of the above-mentioned several measurement technologies is that all measurements are completed in the optical domain, which not only requires the support of expensive precision instruments, but also requires manual adjustment; this makes the equipment cost, time cost and labor cost for completing a measurement relatively high.

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