Measuring device of noise characteristics of laser

Abstract

The invention relates to a measuring device of the noise characteristics of laser, consisting of a conversion system of noise fluctuation of the laser and a detecting and processing system. The measuring device mainly comprises a circulator, a 3*3 coupler, a first photoswitch, a second photoswitch, optical fiber, a first Faraday rotation reflector, a second Faraday rotation reflector, a frequencyshifter, a first photoelectric detector, a second photoelectric detector, a third photoelectric detector, a fourth photoelectric detector, a data acquisition card and a computer. The measuring devicedisclosed by the invention has the capability of simultaneously measuring the noise characteristics comprising the intense noise power spectral density, the phase noise power spectral density, the frequency noise power spectral density, the line width and the Allen variance with frequency instability, of the laser, has the characteristics of high integration level and simpler and more concise structure, has no any limitation to the laser to be measured without an extra active control measure, thereby increasing the measuring reliability of the noise characteristics of the laser.

Description

technical field [0001] The invention relates to a laser, in particular to a measuring device for the noise characteristic of the laser. Background technique [0002] Since the laser is always affected by factors such as the spontaneous radiation of the gain medium, the perturbation of the resonance frequency of the resonator and the loss, the perturbation of the pumping efficiency, the change of ambient temperature, and vibration, the intensity and phase of the laser output light field will fluctuate. , and the frequency is the differential of the phase, so the frequency also fluctuates, and this fluctuation constitutes the intensity and phase noise of the laser. [0003] In coherent laser communication, coherent laser radar and other fields, the laser light source used must have strict phase (frequency) stability. The existence of phase noise will reduce the phase (frequency) stability of the laser, thereby seriously reducing the measurement sensitivity and accuracy of the ...

AI Technical Summary

Problems solved by technology

In order for this scheme to meet the conversion conditions from phase noise to intensity fluctuations, the intensity noise of the laser itself is required to be very small, at a level that can be ignored, which greatly limits the scope of application of this method and reduces the reliability of its measurement.

In addition, this technology requires the two arms of the Michelson interferometer to work in the orthogonal operating point state, and the DC output signal of the interferometer is required to actively feedback the arm length difference of the interferometer, which increases the complexity of the system and limits the Low frequency test capability of the system

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