Mode locked fiber lasers and their application in microwave signal generation

An investigation of mode-locked fiber ring lasers and their applications in photonic generation of microwave signals is presented in this thesis. Both passive mode locking and active mode locking are investigated.; For the passive mode-locking, a fiber laser with figure-eight structure that incorporates a nonlinear amplifying loop mirror as a saturable absorber is proposed and demonstrated. One application of the demonstrated passively mode locked fiber ring laser is to generate high-quality microwave signals. In this thesis, a microwave signal generated by beating the mode-locked longitudinal modes at a photodetector is realized. The results show that the generated microwave signal has low phase noise with high stability.; Multiwavelength mode locked laser can find many applications in optical communications. In this thesis, a multiwavelength passively mode-locked fiber ring laser using cascaded fiber Bragg gratings is proposed and demonstrated. It is different from multiwavelength active mode locking in which the round-trip frequencies for all wavelengths must be identical; for passive mode locking, it is demonstrated theoretically and experimentally that the round-trip frequencies are not necessarily identical. A three-wavelength fiber ring laser that is passively mode locked with non-identical round-trip frequencies is demonstrated. (Abstract shortened by UMI.)...