Research On Millimeter-wave And Multi-carrier Generation Technology Based On Microwave Photonics

With the increasing demand for data rate services,the existing crowded band can no longer be supported.To overcome spectrum congestion and support the demand of future services,a method of using millimeter wave frequency band is proposed.However,the generation of millimeter wave signal beyond 100 GHz in electronic domains face a serious challenge because of restrictions on frequency responses of the existing electronic modules and components.By comparison,photonic generation of Millimeter-wave signal is a promising candidate,which can generate higher frequency Millimeter-wave.At the same time,due to the multi-carrier light source flexibility,flatness and number of spectral lines,it plays an important role in photonic networks.It can effectively improve the vulnerability of single-carrier modulation system to multipath interference.Therefore,the generation of millimeter wave and multi-carrier light sources by microwave photons has attracted much attention.This thesis focuses on the microwave photon local frequency doubling technology and the multi-carrier light source generation technology based on external modulate.By analyzing the physical structure and working principle of common electro-optic modulators,at first,three schemes of frequency doubling are proposed.Scheme one,we proposed a novel scheme to generate octuple-frequency millimeter-wave by setting bias points at symmetric offset voltages away from the Mach-Zehnder Modulator(MZM)half-voltage.Without any optical filter or electrical device,the power of 80 GHz Millimeter-wave signal is 45 d B higher than the other Millimeter-wave signal,which is the Ratio Spurious Suppression Ratio(RFSSR).Scheme two,we proposed a novel scheme for 12-tupled frequency millimeter-wave generation based on only one Dual Parallel Mach-Zehnder Modulator(DPMZM),which is flexible and adjustable.Also,without any optical filter or electrical devices,this method produces a high-quality millimeter wave signal with RFSSR greater than 32 d B.Scheme three,a novel optical millimeter wave scheme using cascaded DPMZM to generate 24 times the frequency of local oscillator is proposed.The scheme can obtain high frequency millimeter wave with RFSSR greater than 28 d B.And then,two multi-carrier light source generation schemes are proposed in this paper.Scheme one,81-line flat multicarrier light source with frequency interval of 2GHz is generated by cascading two DPMZM.The flatness of the light source is about 1.60 d B,and the side-comb suppression ratio is about 14.7d B.Scheme two,a multi-carrier light source generation scheme for cascading two different modulators is proposed.And 50,and 125-line flat multi-carrier light source is obtained by cascading two Intensity Modulator(IM)and one DPMZM.The frequency interval of the 50-line multicarrier light source is 2GHz,the flatness is about 0.45 d B,and the side-comb suppression ratio is about 14.35 d B.While 125-line multicarrier light source has a frequency interval of 0.8GHz,a flatness is about 0.5d B and a side-comb suppression ratio is about 13.60 d B.The scheme proposed in this paper is relatively simple,in which the millimeter wave frequency doubling scheme based on the external modulator avoids the use of filter devices,improves the tunability of the whole millimeter wave band and the stability of the system.It is a potential solution for future Ultra High Frequency millimeter wave applications.At the same time,the multi-carrier light source generation scheme based on external modulator can generate multi-carrier light source with good flatness,adjustable spacing and large number of spectral lines by controlling less variables.