Harbin Institute of Technology

Yisi Dong

PengCheng Hu

Chen Zhang

Jinran Zhang

Wenrui Luo

Wenwen Li

Ruitao Yang

A micro-probe laser frequency modulation interferometric ranging method and system, under the premise of not introducing an absolute laser rangefinder to introduce new uncertainties, continuously and slowly changes the modulated laser wavelength, resulting in a continuous periodic phase change in the interference signal obtained by the detector. The laser modulation absorption spectrum shifts from the initial locked absorption peak to another locked peak, and the wavelength changes of the two locked absorption peaks before and after are obtained by checking the table. Meanwhile, calculating the phase difference demodulated by the phase generated carrier (PGC) before and after, and the initial length of optical dead-path is calculated using wavelength scanning technology. Afterwards, utilizing the advantages of high relative distance measurement accuracy of micro-probe fiber optic laser interferometer, real-time measurement of the measured distance is achieved.

Micro-probe laser frequency modulation interferometric ranging method and system

A frequency stabilization method and system for tunable light sources based on characteristic curve reconstruction are provided, which relate the field of frequency stabilization technologies of modulation absorption spectrum. A set of frequency stabilization control method and system based on internal modulation absorption spectroscopy of light source is constructed, and a high-precision laser frequency stabilization method under large-amplitude and high-bandwidth frequency modulation based on frequency discrimination curve reconstruction is proposed to solve a problem that it is difficult for micro-probe laser interferometry measurement benchmark to balance large-amplitude and high-bandwidth frequency modulation, and high-precision frequency stabilization, resulting in that it is difficult to obtain high relative accuracy measurement under large-range measurement. Under the large-amplitude and high-bandwidth frequency modulation, a distortion model of the frequency discrimination curve and a distortion correction model are constructed, which is used for feedback adjustment of phase compensation and reconstructing the frequency discrimination curve.

Frequency stabilization method and system for tunable light sources based on characteristic curve reconstruction

An interferometric displacement measurement system and method based on phase modulation of polarized light of micro probe are provided. An electro-optic phase modulator is used to perform sinusoidal phase modulation on a light beam emitted by a semiconductor laser to obtain an adjusted light beam. The adjusted light beam is divided by a polarization beam splitter to generate a reference light beam and a measurement light beam. The two light beams are respectively reflected by a built-in reflection surface of a micro probe and a target mirror, and transmitted to a polarization-maintaining fiber circulator. The reference light beam interferes with the measurement light beam at a fiber optic polarization element to generate an interference light signal. A photodetector converts the interference light signal into an interference electrical signal, and the interference electrical signal is demodulated by a signal demodulator to obtain a displacement value of the target mirror.

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Harbin, China

Yisi Dong