Temporal, spectral, and noise characteristics of erbium-doped fiber amplifiers and lasers

A wealth of information can be found in the current literature describing the usefulness of erbium-doped fiber amplifiers and lasers. The goal of this thesis is to examine some of the characteristics of these devices, both theoretically and experimentally, and to explore the potential for adapting them to practical situations.; An erbium-doped fiber ring laser was constructed and various aspects of its operation in the continuous-wave regime were characterized. Fluctuations in the output power were determined to be a result of mode-competition between the counter-propagating traveling waves in the laser cavity. By applying optical feedback to the laser to encourage unidirectional operation, the signal-to-noise ratio was improved by 11 dB.; Measurements on the spectral characteristics of the laser were also taken. When operated independently, the laser oscillated in multiple longitudinal modes. However, through the mutual injection-locking of a distributed-feedback (DFB) laser and the fiber laser, the lasers were forced to operate in a single-longitudinal mode. In addition, the narrow linewidth of the fiber laser reduced the linewidth of the coupled-laser output to below that of the DFB laser.; A theoretical model for the fiber amplifier based on the Bloch equations which makes neither the parabolic-gain approximation nor the rate-equation approximation was used to explore the existence of solitons in a distributed amplifier communication system. Solitons can be supported provided there is enough broadband loss such that the net gain is negative in the spectral wings of the pulse. These solitons are chirped, and the pulse characteristics are strongly dependent on the amount of loss.; The model was extended to analyze pulse generation in modelocked fiber lasers in order to determine the parameters of the laser that effect the widths of the emitted pulses. The spectral sidebands characteristically seen in fiber lasers as a result of dispersive-wave resonances were analyzed. The position of these sidebands was found to be effected by the amount of chirp acquired by the pulse which is determined by cavity losses and gain dispersion.