Research On Fiber Lasers & Fiber Amplifiers In Communication System

With coming of the information era, the rapid evolution of various new communication modes drive the development of super high speed, super high capacity optical communication system. On the other hand, the organic combination of density wavelength-division-multiplexing (DWDM) technology and optical time- division- multiplexing (OTDM) and optical code-division-multiplexing-address (OCDMA) and so on will form the optical network of ultra large capacity fulfilling multiple services. In order to satisfy the request of optical communication system, optical source technique, optical amplifier technique, optical net nod technique, and optical transmission technique, and so on are developing fast and many novel components are emerging. Considering the development and research attention of optical communication, the dissertation includes the detailed descriptions on the following subjects:1. Researches on actively mode locked fiber ring lasersThe active mode-locked fiber laser is studied in detail theoretically, numerically, and experimentally.At first, the essential theory of the mode-locked fiber ring laser is discussed. Then the nonlinear Schrodinger equation is used to analyze the characteristics of the output pulses of the active mode-locked fiber ring laser numerically. The influences of the dispersion, the bandwidth of filter, and the cavity loss on the pulses are simulated in the condition of ignoring non-linear effect.Using fiber grating to substitute traditional wavelength-selecting components, the wavelength tunable active mode-locked erbium-doped fiber ring lasers are obtained. There are three advantages when using fiber grating: a) low cavity loss; b) low cost; c) high stable wavelength.Utilizing large dispersion of a chirped fiber Braggg rating (CFBG), a wavelength tunable mode-locked fiber ring laser is obtained in the band-width of the CFBG. The super-mode noise and environment influence are suppressed since the cavity length is...