Performance Analysis And Hardware Realization Of Optical Frequency Comb Based On IQ Modulation

Optical Frequency Comb(OFC) is a kind of laser source with comb spectrum. It has important applications in many areas, such as arbitrary frequency measurement, optical arbitrary waveform generator, signal procession in microwave photonics, especially in the microwave photonics filters(MPFs) area. MPFs based on OFC have some features which cannot be realized in electronic microwave filters, such as high filter frequency, anti-electro-magnetic interference, and so on.Deriving from the project needs, this paper briefly sketches several different precepts of generating OFC,and proves the necessity of using the IQ Modulator(IQM), meanwhile for the first time brings the small signal model from the cyclic frequency shifter program to the program of generating OFC using IQM with multi-frequency. Then the simulations analyses the relationship of the parameters between microwave signal and OFC when IQM woks in carrier-suppressed-single-sideband(CS-SSB), also analyses the influence causing by some practical factors. And the paper proposes the feedback control process using the maximum-minimum algorithm and the average-tending algorithm to improve the flatness of OFC. On this basis, the hardware of Arbitrary Waveform Generator Module(AWGM) generating microwave signal is designed, also the software controlling AWG from terminal interface. Finally, the experiment platform is performed to verify some of simulation results.The simulation and experimental results are as follow: when IQM works in CS-SSB and under the small signal module, the parameters of OFC have the one-to-one correspondence to that of the microwave signal; both the two algorithms can make the flatness factor of OFC lower than 5%, also the average-tending algorithm is faster than the maximum-minimum algorithm and associated sidebands can be neglected; the schematic design and PCB design of AWGM, also the terminal interface which is based on LabVIEW software platform, are all finished; the control and regulation of the AWG are successfully implemented.