Research Of Programmable All-fiber Structured Flexible-grid Optical Filter And Its Applications

With the rapid development of optical fiber communication systems, there is a transitionfrom static to reconfigurable optical network in order to provide flexible bandwidths andwavelengths for dynamical spectral resources assignment and transmission efficiencyimprovement. As one kind of the key devices in optical communication systems, opticalfilters with flexible-grid filtering function are demanded to satisfy the requirements ofdynamic all optical networks. This thesis is mainly concentrated on linearly chirped fiberBragg gratings (LCFBGs) based programmable flexible-gird all-fiber structured filter and itsapplications. The main research tasks are as follows.(1) The research background of programmable flexible-gird all-fiber structured filter isanalyzed. And the liquid crystal on silicon (LCoS) based flexible-grid optical filter and thebasic theory of LCFBG based flexible-grid optical filter are introduced, and the current stateof tunable optical filter based on LCFBG is summarized.(2) A programmable optical filter based on a LCFBG and a thermal printhead isproposed and experimentally demonstrated. The number of transmission channels,bandwidth per channel, centre wavelength as well as the wavelength spacing can be adjustedindependently. A digitally controlled system for filters is developed.(3) A method of constructing optical temporal differentiators (OTDs) based on ourdeveloped digitally controlled system is proposed, and a wavelength-tunable second-orderOTD is experimentally demonstrated.(4) A multi-wavelength fiber ring laser based on a LCFBG is experimentallydemonstrated, the wavelength, quantity and spacing of lasing channels can be tunedindependently.