PhD Dissertation Defense

In future fiber-optic communication systems, it will be important to increase the transmission capacity. Wavelength-division-multiplexing (WDM) is a technology which can expand the bandwidth of already existing fiber transmission networks by multiplexing multiple optical carrier signals on a single optical fiber. However, current WDM network system uses a single laser source for each wavelength channel, requiring dedicated wavelength control and thermal management. This complexity comes at a significant cost. A very attractive solution to minimize the complexity is to use a multi-wavelength laser source. In this Ph.D. thesis work, we proposed and demonstrated various schemes of multi-wavelength ring laser sources, which can be potentially used in future WDM systems. Stable optical dual wavelength mode-locked operation is achieved in a fiber laser by using nonlinear polarization rotation (NPR) in a highly nonlinear fiber (HNF) or gain distribution in a dispersion compensating fiber (DCF). In addition, a multi-wavelength passively mode-locked laser is also demonstrated. Further research has shown that NPR can also be used to generate an amplitude-equalized dual-wavelength rational harmonic mode-locked fiber ring laser with a data rate up to 40 GHz per wavelength. In order to better understand the mechanism of pulse propagation in optical fibers, self-similar pulse generation and super continuum generation have been investigated.