Research On Optical Tunable And Switchable UWB Signals Generation At Single Wavelength

Ultrawideband technology is a wireless communication technology.It has the characteristics of fast transmission speed,short communication distance,low transmitting power and good secrecy.It is considered to be a promising new technology.Because the traditional UWB signal is the RF signal,the loss is very large in the air,which greatly limits the application scope of UWB technology.The optical fiber has the advantages of large capacity,small loss and so on.Usually we use optical fiber to carry out the long distance transmission of the signal.If the UWB signal is transmitted over a long distance on the optical fiber,the application range of UWB technology can be greatly expanded.If UWB signals are generated using all light methods,it is beneficial for the UWB signal generation system and long distance transmission system to be further simplified and better compatible.At present,there is very little research on optical tunable and switchable UWB signals generation,and there is no research on optical tunable and switchable UWB signals generation at single wavelength.The advantage of producing UWB signals on a single wavelength is that the signals are all at the same wavelength,the rate of transmission is consistent in the optical fiber,so the signal will not go away during the transmission process.And it can reduce the use of devices,the system will be more simple,therefore we need to do more research in this area.In this paper,we use the wavelength conversion of SOA construct a scheme of tunable and switchable UWB signals at single wavelength,which realized UWB signal pulse width and RF spectrum tunable and pulse polarity switchable.The main contents and results are as follows.(1)The establishment of a tunable switched UWB pulse transmission model at single wavelength optical wavelength and the design of its generation schemeBased on the theory of semiconductor optoelectronics,the gain dynamic equation and the optical field propagation equation,then numeric the transfer process,the transmission model of UWB signal in SOA is established.According to the characteristics of the XGM effect in SOA,we use SOA and adjustable delay line devices to delay and combination the two signals,design the generation scheme of adjustable and switchable monocycle and doublet UWB pulses on optical single wavelength.(2)Simulation of tunable and switchable UWB pulse generation at single optical wavelengthTake the previously designed scheme into the model for MATLAB simulation calculation,we can obtained the results of the time and frequency domain of the output signal.Realized monocycle and doublet UWB signal pulse width and RF spectrum tunable and pulse polarity switchable.(3)Experimental research on the generation of tunable switched UWB pulses at single optical wavelengthExperiment research based on the design and optimization scheme,the monocycle and doublet UWB signal pulse were generated,we can obtained the results of the time and frequency domain of the output signal.The monocycle and doublet UWB signal pulse width and RF spectrum tunable and pulse polarity switchable are realized.And the results is fit with the previous simulation results.Then we put the signal into a 20 km optical fiber for transmission.The pulse width is broadened in the acceptable range after the signal is transmitted.