The Research On Characteristics Of Reconfigurable Optical Add/Drop Multiplexer Based On Compound Lattice Photonic Crystals

With the development of new information technology,such as cloud computing and Internet of things,the demand for information transmission in all industries are higher and higher.Optical transmission network has bright prospects because it can provide reliable transmission.Reconfigurable optical add /drop multiplexer(ROADM)is currently the key device for OTN network to enter all optical network stage.It can not only download specific wavelength to local from multi wavelength signal.,but also has the most important ability of dynamic reconfigurable,which accelerates the intelligent process of optical network.In order to make full use of more and more precious bandwidth resources,the wavelength interval will be smaller and the number of channels will be increased.Therefore,the size of the ROADM needs to be integrated and small enough.ROADM based on photonic crystal is of small size and low insertion loss.Therefore,the research of photonic crystal based ROADM is of great significance for the development of all-optical network.A four wavelength OADM based on complex lattice photonic crystal is designed Firstly,the structure of OADM is studied by plane wave expansion method and finite difference time domain method.The principle of uploading and downloading is analyzed by use of the coupled mode theory of point and line defects.The performance of OADM is analyzed using the Rsoft software based on the finite difference time domain method.The simulation results show that the two point defect resonant cavity can be used to realize the four wavelength division multiplexing and the insertion loss is small and the channel isolation is high.On this basis,a ROADM based on complex lattice photonic crystal is proposed.The downloading of different wavelengths is realized by electrically controlled liquid crystal.The simulation results show that ROADM can achieve 1510 nm to 1570 nm wavelength reconfiguration and the download and upload rate is basically over 90%,up to 99.2%.The insertion loss is lower than 0.5dB,the channel isolation is high and more than 20 dB.The reconfiguration time is milliseconds.The ROADM has application value in the development of OTN network.