Optical fiber frequency domain interferometry ranging system and method based on DFB array swept light source

Abstract

The invention belongs to a laser interferometry ranging technology, and provides an optical fiber frequency domain interferometry ranging system and method based on a DFB array swept light source, inorder to improve the contrast of an interference signal to the maximum extent and realize a wide swept range and very good coherence at the same time. Swept laser generated by the DFB array swept light source firstly enters a wideband optical fiber coupler with a light splitting ratio of 20 to 80, and 20% of split light enters a referential Mach-Zehnder interferometer (MZI); 80% of other light passes through a wideband optical fiber coupler with a light splitting ratio of 10 to 90, and 10% of the light enters a reference arm in two interference arms; and 90% of other light enters a test arm, the test arm adopts a three-terminal circulator structure, the swept laser enters an optical fiber probe from the three-terminal circulator and then is emitted to the surface of a to-be-tested workpiece, the reflected light from the surface of the to-be-tested workpiece is collected by the same optical fiber probe, and then the three-terminal circulator enters a coupler for beam combination to interfere with reference light. The interferometry ranging system and method is mainly applied to the laser interferometry ranging occasions.

Description

technical field [0001] The invention belongs to the technical field of laser interference distance measurement, in particular to the measurement technology of optical fiber frequency domain interference gap of frequency-sweeping light source. Specifically, it involves an optical fiber frequency-domain interference ranging system based on DFB array-sweeping light source. Background technique [0002] Many industrial, scientific, and military systems require reliable, high-resolution methods to measure distance while having stringent sensor size, power, and complexity requirements. For example, clearance measurement in major equipment such as engines and steam turbines, as one of the key parameters affecting the operation performance of large equipment, is widely used in national production and national defense. As the core component of the thermal power unit, the axial clearance of the steam turbine is one of the key indicators to improve the thermal performance of the super...

AI Technical Summary

Problems solved by technology

The problem is that it fundamentally depends on the frequency-stabilized laser with moderate spectral line distribution; different frequency-stabilized lasers are suitable for different measurement ranges and accuracy requirements

At present, the mature methods are mainly aimed at the measurement range within 5mm, but there is little research on gap measurement with a measurement range of about 10mm, and there is a lack of technical support

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