Study On Optical Frequency Comb Based On Optical Injection Technique

In this modern information age,the demand for information is increasing rapidly.In order to meet the development trend of the modern information technology,a new research field was born,named microwave photonics.It combines the advantages of the high-resolution of the microwave and the large bandwidth of the optical wave,and has great potential in promoting the development of the modern information technology.The research of optical frequency combs(OFCs)is an indispensable part in the field of microwave photonics,including high-precision microwave photonic measurement and ultra-fast optical signal detection or measurement.OFC is an ultra-short optical pulse laser in essence.In frequency domain,its frequency spectrum appears as comb lines with equal frequency interval,shaped like a comb.As a multi-wavelength coherent light source,OFC plays an important role in the research of microwave photonics.Hence,it is important to obtain high-quality OFC in the related scientific research fields.In this thesis,a seed OFC is generated based on the period-one oscillation characteristics of an optically injected semiconductor laser.The spectral range of the seed OFC is expanded by using the sub-harmonic modulation technology and the optoelectronic feedback loop technology to generate a high-quality OFC.The main work of this thesis is as follows:1.The research background of the OFC and several typical generation methods andschemes are introduced.Both the advantages and disadvantages of these methodsare analyzed.The development status and future trend of the OFC are alsosummarized.In addition,the distinguishing feature and application status of theoptically injected semiconductor laser technology are briefly presented.2.Based on the classical rate equation model of the optically injected semiconductorlaser and the two changed models considering the sub-harmonic modulationtechnology and optoelectronic feedback loop technology,respectively,numericalsimulation is performed in Matlab.When the semiconductor laser is in the state ofthe period-one oscillation,the effects on the generated seed OFC with the changesof the injection coefficient and the detuning frequency are investigated Moreover,the changes in the quality of the seed OFC are studied by employing thesub-harmonic modulation technology and the optoelectronic feedback looptechnology.3.The two techniques for improving the quality of the seed OFC are experimentallystudied:(1)the sub-harmonic modulation technique;(2)the optoelectronicfeedback loop technique.Experimental results show that both of the two techniquescan improve the quality of OFC significantly.One17-lines OFC is obtained usingthe sub-harmonic modulation technology,with a comb tooth spacing of 4 GHz anda flatness of 2.3 dB.The optoelectronic feedback loop technology can evokeself-oscillating and suppress noise simultaneously.Thus the structure is simple andcompact without external microwave signal sourceOne20-lines OFC is obtainedusing this optoelectronic feedback technology,with a comb tooth spacing of 4 GHzand a flatness of 2.3 dB.