Study Of The Generation And Transmission Performance Of Millimeter Waves Based On Optical Multiplication

The radio-over-fiber (ROF) system, which brings the huge capacity of optical communication and the agility of wireless access together, will be a perfect technology in the future broadband wireless access services, and it has been a research hot spot in optical fiber communication. Optical mm-wave generation is one of the key technology in ROF system. In this thesis,several schemes of mm-wave generation and transmission are proposed and The results obtained are as follows:Firstly, two schemes of 40GHz quadruple mm-wave generation are proposed and realized: scheme 1:odd order sidebands are suppressed by adjusting the DC bias of the LiNbO3 Mach-Zahnder Modulator (LN-MZM) to be 3.9V, then we use Fiber Bragg Grating ( FBG) filter to filter out the optical carrier, two second order sidebands beat to generate 40GHz quadruple mm-wave, the downlink data transmits 40km in fiber with less than 1dB power penalty in the experiment. demonstrated. Scheme2: we also realize the modulation format which odd order sidebands and carrier are suppressed simultaneously by adjusting the DC bias to be 0V and RF voltage to be 6.12V and also the phase difference to be 90. Two sceond order sidebands are left to generate 40GHz mm-wave signal. We have two different method to realize data signal upconversion: firstly, we use the data signal to modulate the directly modulated laser; Secondly, the intensity modulator is modulated by the data signal. The first directly modulation format can generate modualtion chirp and it affects the transmission distance. The second external modualtion format makes the downlink data transmits 70km which is 30km longer than the first one.Secondly, a scheme of 60GHz sextuple mm-wave generation are proposed and realized: we generate modulation format which first and second order sidebands and carrier are suppressed by adjusting the DC bias to be 4V and RF voltage to be 9.76V and also the phase difference of the RF to be 180.The phase difference is 180 generated by DC voltage. Two third order sidebands are left to generate 60GHz mm-wave signal.. We have two different method to realize data signal upconversion: firstly, we use the data signal to modulate the directly modulated laser; Secondly, the intensity modulator is modulated by the data signal. The first directly modulation format can generate modualtion chirp and it only transmits 30km. The second external modualtion format makes the downlink data transmits 40km. Finally, a scheme of 40GHz eightfold mm-wave generation are proposed and realized: we use two LN-MZMs with parallel connection, both of which were used to generate signals which odd order sidebands and carrier are suppressed. Then the two signals are coupled to transmit along fiber, because the second order sidebands of the two generated signals have the opposite phase, only the fouth order sidebands are left to generate eightfold mm-wave signal.