Design Of Control System For Transportable Ytterbium Atomic Optical Clock

In recent years,the optical frequency standard based on neutral atom and single ion has got rapid development.Its stability and uncertainty are much better than that of the cesium atomic microwave clock,which is now as the reference of the second definition.The new second definition with optical clock needs to be based on the frequency comparison between optical clocks and between optical clocks and cesium fountain clocks.Therefore,due to the global coverage of commercially available optical fiber links,transportable optical clock is an important way to achieve clock comparison.At the same time,transportable optical clocks and even space optical clocks have gradually shown their important applications in high-precision navigation and positioning,high-precision measurement of geoid changes and verification of relativity effects.Moreover,ytterbium(Yb)atomic clock,with the best stability,has attracted extensive attention.Based on the above research,this thesis is focused on the control unit of transportable optical clock,which is of great value for the stability,engineering and miniaturization of the transportable Yb atomic clock system.It revolved around the implementation scheme,functional parameters selection and fast data analysis and processing ability with field programmable gate array(FPGA)hardware design.The main results during my master’s period are summarized as follows:1.The function of programmable optical switch is realized with FPGA hardware.The results show that the rising edge of the optical switch is about 10 ns and the falling edge is about 5 ns.The stable RF signal with the frequency of 0-400 MHz and the maximum output power of 0 dBm can be generated,which can meet the timing control requirements of the clock operation;2.The acquisition and processing of analog signal and digital signal is realized with FPGA hardware.The collected signal can be converted into digital to analog or analog-to-digital signal.The resolution of DAC is 16 bits,and the operation rate is 1 MSPS;ADC resolution is also 16 bits,and sampling rate can reach 1.5 MHz.3.Rapid data processing is realized with Python program.It takes about 11.98 s to process the clock transition spectrum and 14.47 s to process the cold atom image.The results show that data processing with Python program can be perfectly matched with traditional method dealt with Matlab and Origin program.Fitting to the complex clock transition spectra with multi-Gaussian superimposition can act as a method for machine learning,which is a better way for experimental process analysis and fault diagnose.