Photonic Microwave Waveforms Generation Technology Based On Optical Injection Locking And External Modulation

Photonic microwave generation technology can easily break through the electronic bottleneck,achieving the frequency multiplication of microwave signal and the generation of high frequency microwave signal.The technology has the advantages of electromagnetic immunity and low cost.It also has a wide range of applications in radio-over-fiber systems,measurement systems,radar,and so on.The photonic microwave signal can be easily obtained by using the injection-locking process of semiconductor laser and the process of optical external modulation.This work mainly focuses on two aspects,the frequency multiplication of microwave signal and photonic generation of radio-frequency arbitrary waveforms.All in all,the following research works have been done in this paper.A frequency-doubled triangular waveform generation scheme based on the modulation characteristics of single-drive Mach-Zehnder modulator and optical injection-locking process is proposed.On the basis of the original scheme of our research group,the generation of the frequency-doubled triangular waveform is achieved by improving the previous design.The theoretical analysis is established.In the experiment,sinusoidal modulation signals at the frequency of 3GHz and 4GHz are applied to generate full duty triangular waveform with a frequency of 6GHz and 8GHz successfully.An arbitrary waveform generation scheme based on two cascaded single-drive Mach-Zehnder modulators is proposed.The modulation character and the polarization sensitivity of the modulators are fully exploited and utilized.The detailed theoretical analyses and simulations are given.In the experiment,square-shaped waveform,triangular waveform,sawtooth(or reversed-sawtooth)waveform and width-adjustable pulse are obtained successfully.Moreover,the relevant research contents are further discussed.