Research On A Online Monitoring Method Of Optical Power In Every Core In Fiber Tapering

With the development of the optical fiber technology, especially the appearance of thespecial optical fibers and microstructure fiber brings vitality and vigor for the developmentand application of integrated optics, and optical switch, laser, the optical coupler, fibercommunication devices and optical fiber Raman amplifiers based the above fiber are widelyused in all fields. However the special waveguide structure of microstructure fiber preventsthe realization of high efficiency coupling connection, so the manufacture of couplers andprocess monitoring will become the key technology of production of fiber devices. Forpractical monitoring problems in coupling process, the method to achieve real-timemonitoring based on FPGA is put forward to provide safeguard for the production ofmicrostructure fiber. The major research work in this paper is as follows:Fiber couplers and related measuring and testing techniques were summarized, and basedon the microscopic imaging technology and fiber melting technology, the monitoring methodof optical power in every core of fiber was put forward, this method is supported bymicroscopic imaging system and image processing system, taken high speed data flow as thecore design, achieved by programming image preprocessing module and light poweralgorithm module.Further study the basic theory of optical waveguide, explore to established a couplingmodel between single core fiber and multi core fiber, based on the light wave length of lightsource, the distance between fiber cores, the length of interaction and other factors on theeffect of light power in coupling. By building a new fiber splicing and tapering method,reducing the problem to looking for welding spot after the traditional splicing and carry outthe coupling and tapering and the distribution of light power more conveniently.Take CMOS image sensor which type is MT9V403for core device, based on FPGA andDSP technology, measuring and testing platform of optical power in core was established tocomplete the drive of the image sensor chip, data transmission, data processing, and otherfunctions. Design of image window program based on Verilog HDL is deeply studied,achieve data transmission of specified space images information, so as to be provided by thereal-time performance.Carrying out the study of light power monitoring algorithms based on DSP, through the peak detection, characteristic regional determination, gray accumulating, normalization andother image processing methods, complete measurement of distribution of power shot out ofcores, accordingly, achieve purposes of real-time monitoring and controlling light powerallocation in every core.This paper take the microscopic imaging system as the foundation, and take the methodof image information processing based on FPGA and DSP as the core, use pipeline design formonitoring program, carry out ping-pong operation of image data, realized seamless databuffering and processing, complete fast calculation for optical power in every core ofmulti-core fiber, Solve commendably difficult problems of online real-time monitoring intapering. The functional modules of the system take the independent design, is easy to codeand modify, and has high system integration, so it is easy to debug and miniaturize.