Abstract:

Developments of long haul high speed transmission systems based on soliton technique have been driving factors for many researching efforts of developing the ultrashort pulse sources at high repetition rate. Although there are some reliable techniques to generate the transform-limited short pulses, recent studies have shown that actively phase- or frequency-modulated mode-locked fiber lasers are becoming a promising candidate as soliton generator for high speed optical fiber transmission and signal processing systems. The attraction of the FM mode-locked fiber laser in research is not only due to generation of stable ultra short soliton pulse sequence at speed of tens of GHz but also other dynamic behaviors of mode-locked pulses in strongly nonlinear regime of operation. An actively FM mode-locked fiber laser consists of a close-loop fiber ring cavity with optical amplifiers, optical phase modulator and a fiber length. New dynamic characteristics of solitons such as bound states recently have attracted significant research interests in the passive mode-locked fiber lasers, yet there are still challenging questions to be answered in active mode-locked fiber lasers. 

This PhD research program will focus on detailed study of the multibound solitons in actively nonlinear mode-locked fiber lasers, especially when they are operating from stable to bistable regions. From our initial phase investigations, the experimental results demonstrate the existence of multibound soliton states in a FM mode-locked fiber laser incorporating an optical phase modulator in the ring cavity. We note that it is the first time, to the best of my knowledge, that bound solitons have been successfully demonstrated in an active fiber ring structure incorporating an electro-optic modulator. Thus through experimental works and simulations, the bound soliton states as well as their formation mechanisms will be investigated in the FM mode-locked fiber laser in the remaining period of my candidature. Furthermore, potential applications using multi-bound soliton source at high speed will also be projected.

About the Speaker:

Duc Nhan Nguyen is a PhD student with the Department of Electrical and Computer Systems Engineering at Monash University