Laser self-mixing interference system with feedback light intensity self-adaptive adjustment function

Abstract

The invention discloses a laser self-mixing interference system with the feedback light intensity self-adaptive adjustment function. The system is composed of a laser, a driving power source, a photoelectric detector, a transimpedance amplifier, a filter, a data acquisition card, an upper computer, a micro controller, an isolation amplification circuit, a stepping motor, a transmission mechanism and an adjustable attenuation sheet, wherein data from the data acquisition card are read by the upper computer, the output power waveform of the laser is restored through processing, and modulation factors affecting the power fluctuation range are extracted from the output power waveform and loaded into the micro controller. According to the proportion relation between the modulation factors and a feedback intensity coefficient, the feedback intensity coefficient is acquired after data processing is performed in the micro controller and compared with a pre-input ideal intensity coefficient, a pulse signal is output according to a comparison result so that the stepping motor can be controlled, the attenuation sheet is driven to rotate so that the attenuation rate can be adjusted, and the purpose of adjusting the feedback light intensity can be achieved.

Description

Technical field [0001] The invention relates to the technical field of laser self-mixing interferometry, in particular to a laser feedback intensity adjustment method and device. Background technique [0002] In recent years, the laser self-mixing interference technology has gradually matured, and more and more measurement applications based on this technology. Compared with traditional interferometers, self-mixing interferometers are simple, compact and easy to collimate. They have gradually replaced traditional interferometers and have been widely used in many occasions, such as the measurement of physical properties and motion characteristics of objects: topography Measurement, displacement and distance measurement, speed and vibration measurement, etc. The laser self-mixing interferometer is based on the phenomenon of laser self-mixing interference: when the light emitted by the laser is incident on the surface of the object, it will be reflected or scattered on the surface ...

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Problems solved by technology

However, in "Research on self-mixing interference effect and micro-vibration measurement of semiconductor lasers under moderate feedback" (see "Optoelectronic Technology Application", 2013, Vol. It cannot be achieved, especially when the target to be measured is small, and cannot be achieved by fixing a specific reflectivity on the target

The measurement method of the feedback intensity coefficient proposed in "Research and Measurement of Feedback Level of Optical Feedback Self-mixing Interference System" (see "Laser Technology", Volume 36, No. 6, 2010) uses the difference between the peak value of the waveform of the interference signal or the Using the waveform hysteresis phenomenon, the method of obtaining the feedback light intensity coefficient through a series of numerical operations is more complicated in practical application

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