Research Of Laser And Fiber Phase Noise Technology Control For Strontium Optical Clock

In modern society,the application range of optical technology has been wider and wider.In order to implement fiber transmission on multi-platform,fiber is usually used as transmission medium of optical standard signal.However,in the process of optical standard signal technology on fiber transmission,there is interference due to some factors,including power shake and phase noise caused by fiber transmission.In order to cope with changeable environment and complex requirements of strontium optical lattice clock experiments,laser power stabilization is required with timing control capabilities.In this paper,acousto-optic modulation is adopted to stabilize the laser power,based on the principle that diffraction efficiency of the acousto-optic crystal varies with its driving radio frequency power.A feedback control system is established,realizing active stabilization of the laser power and the ability of power set point switching with timing control.At the same time we should restrain fiber phase noise on fiber transmission,and satisfy the requirements of narrow-wire wide optical standard signal technology on fiber transmission.Our paper uses acousto-optic modulation as keying technology,and basic principle as supported theory.The phenomenon that 1 stair and-1 stair diffraction efficiency of the acousto-optic modulation varies with its driving radio frequency power is also used in the paper.A system of restrained phase noise on fiber transmission is built to improve the frequency stability of optical standard signal on fiber transmission.After testing the two experiments above,we analyze the results and get the conclusions below.The laser power can be set at arbitrary levels within its setting range according to the time sequence.When the control system is enabled,the relative laser power stability is improved from 10-2 to 10-4 compared with the state when it is disabled.The advantage of the system is the timing control stability on power.In the restrained fiber phase noise system,laser and its reflector use the method of beating frequency with itself to detect fiber phase noise signal.Phase locked loop control system is used to restrain fiber phase noise.As the experiment results show,when the system is locked,the frequency width of beat signal decrease from 102 to 10-1.The frequency stability of beat signal denoted with ALLAN variation is improved from 10-6 to 10-12.Thus,the influence of fiber phase noise on laser frequency stability is successfully restrained.