Research On High-performance Communication Light Source Based On Kerr Comb Of Whispering Gallery Mode Microcavity

With the rapid development of broadband Internet,cloud computing,big data and other emerging technologies,network traffic continues to grow rapidly,and it is increasingly important to further increase the capacity of communication networks.In the large-capacity optical fiber transmission system,further increasing the transmission bandwidth and reducing the signal noise to increase the communication network capacity puts forward higher requirements on the communication light source,so the research on the new high-performance communication light source is indispensable.This thesis has carried out related research work on whispering gallery mode optical microcavities and kerr combs from the perspective of the application of high-performance communication light sources.The main contents and innovations are as follows:The theoretical and experimental basis of the whispering gallery mode optical microcavity are introduced,and three important parameters that characterize the whispering gallery mode optical microcavity are introduced:quality factor,free spectrum range and mode volume.Then several common coupling systems of whispering gallery mode optical microcavities are introduced.The preparation process of the microcavity and tapered fiber and the coupling test process of the microcavity are described,and the performance of the microcavity is optimized from the processing strategy and the coupling strategy.The number of modes is controlled to 1-5,and the quality factor reaches10⁸.The auxiliary laser heating method is used to extend the soliton existence range of the red detuning region in the microcavity by 60 times.By manually tuning the pump laser wavelength to successfully enter the red detuning region,a single soliton optical frequency comb with a spectral width of 24 nm is generated,through simple adjustment the distance between the tapered fiber and the microcavity can be observed to increase the energy conversion efficiency of the optical frequency comb by 10 times.Then lock the two high-power and low-cost DFB lasers to the optical comb respectively to amplify the comb tooth power as a carrier,and compare its communication quality with that of the optical comb directly filtered and amplified as the communication light source.In the communication experiment,the modulation format uses 16QAM,and the signal bit rate is 75Gbit/s.In the experimental results,the carrier signal-to-noise ratio(SNR)has increased from 34.3d B to 61.0d B,and the bit error rate(BER)is reduced from 7.8×10^-2to 3.5×10^-3 and from 8.0×10^-2 to 1.7×10^-3 at the two channels of 1550.972nm and1551.144nm respectively.Demonstrating the feasibility of the new communication light source proposed in this article.On the basis of the realization of the new communication light source scheme,this paper also studies the content of light source packaging integration,and optimizes the number of excitation modes and quality factor by adjusting the coupling coefficient.On this basis,a new type of piezoelectric ceramic-based echo is proposed.The whispering gallery mode optical microcavity packaging method has been tested for its coupling tunability and stability over 1 hour.Finally,the packaging structure was successfully used to generate a kerr soliton optical frequency comb with a stable duration of over 1 hour.