Tunable Optical Frequency Comb Technology Based On Recycling Frequency Shifter Loop

In recent years,optical frequency comb has become an ideal light source for optical communication systems due to its advantages of simple structure,low cost and easy operation,and has a wide range of application scenarios in the field of microwave photonics.In order to promote the further development of optical frequency comb technology,it is particularly important to pursue a better optical frequency comb.This paper first researches on the mechanism from the optical frequency comb,mainly study the cycle frequency shift plan the high side,the optical frequency comb mode rejection ratio,tunable comb spacing and comb tooth root of the number of controllable,then use the unique time and spectral characteristics,the optical frequency comb,in the direction of the application of frequency measurement has carried on the exploratory research,specific work is as follows:1.For the scheme of generating optical frequency comb based on cyclic frequency shift,the factors affecting the performance of output optical frequency comb in the scheme structure are introduced,including the RF drive signal and DC bias voltage of IQ modulator,the output saturation power of amplifier and the central wavelength of laser.Combined with the simulation results,the conditions for producing high quality optical frequency combs and the maximum offset range of relevant parameters are analyzed.First,in the process of producing single side band of IQ modulator,in order to obtain high power SNR,it is necessary to ensure that the RF signal amplitude is satisfied <1.17V?;Second,if the side mode suppression ratio is to reach 30dB,then the phase deviation value of the two RF drive signals loaded on the IQ modulator should be about 0.02?,the power deviation value should be within 0.5dB,and the accurate position of the DC bias voltage deviation should be about 0.02 V?.2.A phase shifter is introduced into the electrical domain module of the traditional cyclic frequency shift structure to optimize the output performance index of the optical frequency comb.Then a cyclic frequency shift platform is built according to the experimental structure and relevant experimental results are given.Finally,90 controllable optical frequency comb lines are obtained with the comb tooth interval of 9-14GHz and the flatness of 2.8dB.3.using the recycling frequency shifter loop to produce high quality optical frequency comb,verified by the simulation on the direction of the instantaneous frequency measurement scheme feasibility,aiming at the existing blind spots of the scheme are given improvement plan,lead to a special frequency multiple progressive type optical frequency comb,and using this scheme,the measurement of the frequency of the signal under test,finally,the simulation analysis of four different location of the typical frequency point to verify the effectiveness of the proposed scheme,and the correctness of the algorithm.To sum up,this paper studies the generation mode of optical frequency comb and the application of optical frequency comb from two dimensions.The scheme of generating optical frequency comb based on cyclic frequency shift is not only simple to implement the system,but also has strong flexibility and high stability in output optical frequency comb.