Technical Research On Multiple Frequency Signal And Triangular Waveform Based On Cascaded DDMZMs

Microwave photonics is a subject which combines technology of microwave and photonics.As a new inter-discipline,it has advantages of low loss,large bandwidth,anti-electromagnetic interference,small size and light weight from photonics and flexible access from microwave.Microwave photonics utilizes optoelectronic devices and optical methods to solve problems or optimize performance in traditional microwave system,which brings more applications and broader development space for photo-communication and microwave communication.Microwave photonics generation is one of the main technologies in microwave photonics,which can solve the “electronic bottleneck” of frequency,bandwidth and velocity.It can generate high frequency signal utilizing signal source with low frequency,which can avoid using expensive high frequency signal source,decreasing the cost of system.Triangular waveforms have extensive applications in radar systems,signal processing,wireless and wired communications,etc.Due to the limitation of the “electronic bottleneck”,techniques of electronic to generate triangular waveform cannot satisfy the needs of frequency,velocity,loss,etc.In order to break the “bottleneck”,microwave photonic techniques have been one of the research hotspots in recent years.First,this article gives some typical schemes of microwave photonics generation.And then this article introduces the key devices in microwave photonics system,such as electro-optical modulator,polarizing device,photoelectric detector.After that,a new scheme of microwave photonics generation based on DDMZM with tunable multiple factor is proposed,and the conditions of different multiple factor are obtained.On the basis of simulation through VPItransmission Maker,the relation of the RFSSR and modulation index,the gain of the amplifier and the stopband attenuation of the filter are all obtained.And the structure of DDMZM is superseded by the combination of the Pol M,Pol and PC to avoid the bias drift of MZM.And then microwave photonics generation combines with Ro F to discuss how to overcome the chromatic dispersion when optical microwave is modulated by baseband signal.At last,the structure based on DDMZM is utilized to generate triangular waveform.The condition to generate triangular waveform and the performance of that are given in detail.