Fabrication And Properties Of Fiber Grating Gain Flattened Filters For EDFA

Today, there are kinds of gain flattened solution for EDFA, between them, fiber grating GFF have the advantage as low cost, low insert loss, easily coupling, was used mostly. Fiber gratings GFF include FBG, TFBG, LPG, CFBG, LPG, CFBG are more practical, so became the main content of this paper,In respect of theory, we strictly deduced couple mode theory that describe the principle of fiber gratings from Maxwell equation, chirped and analysis the properties of chirped fiber grating, obtain the relationship between chirped fiber grating's parameters such as change of refractive index, length and chirp as well and the properties such as reflectivity, bandwidth and dispersion. For long period gratings obtain the relationship between the transmission, wavelength, photo-induced index variety and period. All of these prepare for the design and fabrication of fiber gratings for EDFA gain flatten.Experimentally, We use program controlled scanning expose technique and phase mask methods for the fabrication of chirped fiber gratings on hydrogen loaded standard fiber. The chirped fiber Bragg grating gain flatten filter for EDFA have designed and fabricated, for 1525～1560nm the gain variation is within±0.3 dB.After fabricated, the CFBG GFF has been annealed at 80℃for8hours, Anneal craft guarantee stability of device can make working life above 25 years. Compared with the situation that other gains smooth technology, need pieces of wave filter not to be can cover the method very heavy table the wide alone(> 35nm), so encapsulation is very small in size.Package the grating using negative temperature coefficient material. After that the grating temperature excursion coefficient is lower than 1pm/℃We also fabricated LPG with the period for 460um and 1/2 occupy using...