Method and device for restraining light source intensity noise through electro-optical modulator proportional compensation

Abstract

The invention discloses a method and device for restraining light source intensity noise through electro-optical modulator proportional compensation. A light beam splitter is used for splitting lightsource output in proportion; a pair of high-power and low-power light beams is formed; the high-power light beam is sampled; light intensity fluctuation information is obtained, a modulation signal isloaded to an electro-optical modulator through a signal processing module to modulate light intensity fluctuation of the low-power light beam so as to generate a light signal which is the same as thehigh-power light beam in intensity and has a phase difference of 180 degrees, and finally the light signal and the high-power light beam are combined and output, so that the effect of restraining output light intensity fluctuation is achieved. The defect of low power threshold of the electro-optical modulator is overcome, the intensity noise suppression of the high-power laser is realized, the cost is low, and the application and implementation are easy.

Description

technical field [0001] The invention relates to a method and a device for reducing the intensity noise of a light source, in particular to a method and a device for reducing the intensity noise of a light source by using an electro-optic modulator to compensate light intensity fluctuations. Background technique [0002] According to the photodetection theory, when a photodetector receives an optical signal input and converts an electrical signal output, there are mainly two noise sources. One is the shot noise of the photodetector. Due to the particle characteristics of light, even if the average intensity of the incident light remains unchanged, the number of electrons emitted by the detector fluctuates randomly, and fluctuates randomly around a statistical average. The power spectral density of shot noise is proportional to the light source power P, as follows: [0003] [0004] In the formula, is the average optical power of the incident light, h is Planck's const...

AI Technical Summary

Problems solved by technology

The pattern cleaner method has obvious suppression effect on intensity noise, but has limited suppression effect on low-frequency intensity noise

The semiconductor optical amplifier saturation suppression method uses the gain saturation characteristics of the optical amplifier to suppress the light source intensity noise, but it cannot meet the high-power input requirements of the optical trap sensing system due to the limitation of the input optical power of the amplifier.

The traditional optoelectronic feedback method is to sample the output optical signal and feed it back to the acousto-optic modulator or electro-optic modulator to adjust the optical power to achieve the effect of noise suppression, but the response bandwidth of the acousto-optic modulator is low, and the optical power of the electro-optic modulator The power damage threshold is low, which is limited in the application of optical trap sensing systems

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