Cascaded Optical Frequency Comb Generation Method Based on Recirculating Frequency Shift
Based on the dual parallel Mach-Zehnder modulator and recirculating shift frequency method,a flat cascaded optical frequency comb generation system is designed in this paper.The system adopts a two-stage structure,a phase modulator is used at the first stage to generate two coherent optical carriers with a certain frequency interval,which are used as two input seed lights of recirculating shift frequency loop at the second-stage.Each seed light generates a sub-comb by recirculating frequency shift in the loop,and the two sub-combs are cascaded into a wider bandwidth optical fre-quency comb.The theoretical analysis model of the system is established,and the system simulation is performed by using VPI software,a 104-line optical frequency comb with a frequency interval of 12.5 GHz and a flatness of 1.31 dB can be obtained.The simulation results agree well with the theoretical analysis.
optical frequency combrecirculating frequency shiftphase modulatorcascade