The Research For Sampled Fiber Bragg Grating Spectral Characteristics And Its Application In OADM

With the increase of high-speed communication services and the number of access users.Dense Wavelength Division Multiplexing (DWDM) technology has become the best solution of thefield of optical communications. Sampled Fiber Bragg Grating (SFBG) has both of the reflectioncharacteristic of the Bragg Grating and long period grating coupling characteristics of the claddingmode, and also has a multi-channel filter function. So Sampled Grating based on optical add-dropmultiplexer (OADM) will have broad application prospects in dense wavelength divisionmultiplexing system.This article focuses on the spectral characteristics analysis methods of SFBG, put forwardseveral common apodization function, SFBG spectrum optimization, the final design of a novelOADM structure, and research its output characteristics. The main tasks are:（1）Introduced the overview of the development of the field of optical communications, briefanalysis of the common structure of OADM, and brief description the basic overview of fibergrating, use three more profound theoretical methods analysize fiber grating, obtained theconclusion is grating reflectivity proportional to the grating length.（2）Use transfer rectangle method, by adjusting the sampling period P duty cycle T andrefractive index modulation amplitude n effparameters, obtained rectangular SFBG reflectionspectrum regulation regularity.（3）Proposed six common apodization function,rectangular SFBG spectral optimization，Apodization function include: Gauss Apodization, Hamming Apodization, Sinc Apodization,Blackman Apodization, etc. Obtain several apodization functions best optimization coefficientobtained by simulation.(4) Sampled grating has been optimized on the basis of the sampled grating-based Mach-Zehnder interferometer instrument OADM, the structure has a multiple channel filtering function. Itcan be found that the interferometer arm length difference and sampling grating center wavelengthare determined the OADM output characteristics. The OADM can achieve signal channels dropadjustable or pass the channels by adjusting the Mach-Zehnder interferometer arm lengthdifference and the sampling grating center wavelength. The theoretical analysis and simulation ofthe structure of the entire OADM,obtained good output spectral characteristics.