All-Optical Add/Drop Multiplexer With Magnetostrictive Tunable Fiber Bragg Gratings

It has been over two decades since the first experiment of fibercommunication was operated in 1978. Fiber-optic communicationtechnologies have been put into commerce step by step. The speed offiber-optic communication has been growing from 45Mbits/s to 10Gbit/s. Sofar, the WDM system is point-to-point arterial system. As long as thesesystems are connected the defects will be discovered. It is a serious problemthat the function of add/drop aren't flexible at the knot. When the nativework of the current knot is extracted from the main line by means oflight/electricity/light and the information is transmitted to the main line,the transmission speed will be limited by electric components. This is whatnamed electricity bottleneck. For this reason,people are attracted by theOptical Add/Drop Multiplexer(OADM) with the add/drop function. Newhigh performance OADM is a kind of key component in WDM networks.Optical add/drop multiplexers are designed to add to the network signalstream and drop out one wavelength channel. OADM can carry out themultichanne operation of adding/dropping in high speeding network withoutlight/electricity/light transmission. The complexity of the software andhardware be simplified which makes the add/drop work be carried outconveniently. It makes the information connect practicable for users. It alsomakes the all-optic networks wavelength recycled, which improves theefficiency and flexibility of networks. During the postgraduate study, the author gained the pleasure to takepart in many scientific researches masterminded by tutor Guo Yubin,including the following project:All-fiber Type Multichannel Add/DropMultiplexer Based on Magnetically Tunable Fiber Bragg Grating. Under theguidance of tutor Guo, I engaged in the design of structure and study of 91吉林大学硕士学位论文experiments. A all-fiber optical add/drop multiplexer based on tunable fiberBragg gratings is designed. Literature search shows that there are notachievements and research in this area is in vogue. Consequently, this thesiswill unfold the study focus on this point, in the expectation of offering thetheory and experiment reference for the methods of tuning FBG anddevelopment of OADM products. The paper contents five parts, of which the first parts are basics. Thesecond and the third part gives an academic research, meanwhile the forthand the fifth parts give a practicing research. Firstly, Available OADM(Optical Add/Drop Multiplexer) are summarized and compared currently. Inthe schemes of their structures,all of them are classified to 5 types :OADM using division multiplexing element,wavelength switching elementand multiplexer,OADM using WGR(Wavelength Grating Router),OADMusing AOTF(Acoustic Optical Tunable Filter),OADM using DMUX/MUX(Demultiplexer/Multiplexer),and OADM using coupling element,filteringelement and multiplexer.The operational principles , configurations ,characteristics,technical level and key technologies of OADM are generallydescribed. Providing basis and references is aimed for growing relatedtechnologies,developing OADM products and designing WDM systembased on OADM. Secondly, in the paper OADM using coupling element,filtering elementand multiplexer is put. The coupling element adopts optical circulator. Thefiltering element adopts FBG , Fabry-Perot cavity , or filter. Thewave-combiner adopts multiplexer. The tuning speed of tunable filter basedon FBG is fast,the spectral width is wide,the stability is better,the price ischeap. The capacity of OADM is determined by the function of filteringelement. A novel multichannel-switching active add/drop multiplexer(OADM) is proposed and demonstrated, which is composed of a pair ofcirculators and fiber Bragg gratings (FBG). Using four identical tunable 92吉林大学硕士学位论文FBGs, together with the wavelength-overlapping technique, an all-optic...