New schemes of picosecond pulse generation with broad tunability in wavelength and repetition rate.

摘要

Picosecond optical pulse sources with broad tunability and various repetition rates are key elements for applications in wavelength- and time-division multiplexed optical transmission systems. Mode-locking is one of the main techniques for the generation of optical pulses with high repetition rate picosecond pulse trains. This thesis presents our research efforts in high repetition rate optical pulse generation using active and regenerative mode-locking techniques, and a self-starting approach. We also demonstrate the application of harmonic mode locking in all-optical clock recovery from NRZ data.; Active mode locking is one of the simplest ways to generate picosecond pulses at gigahertz repetition rates. In my works, I demonstrate the generation of picosecond pulses with a center-wavelength spanning from 1489nm to 1589nm using a polarization maintaining fiber loop mirror filter (PMF-LMF) in a mode-locked semiconductor optical amplifier (SOA) ring laser. By applying the SOA gain shifting technique and with the help of the controllable transmission ratio of the PMF-LMF, the tuning range of the output wavelength can be extended. By applying the technique of dispersion tuning, electrical wavelength tuning can be achieved across a range of 100nm.; Compared to the active mode-locking method, the regenerative mode-locking is very convenient because it does not require any external source for modulation and is proved to be more robust against fluctuations in ambient temperature. We demonstrate a 10-GHz regeneratively mode-locked fiber laser using a PMF-LMF. The operating frequency is determined by the free-spectral-range of the PMF-LMF and the component is extracted optically from the ring laser output.; In addition, we also demonstrate a simple technique to generate wavelength tunable picosecond pulses at adjustable repetition rate without using electrical or optical RF filter to extract the radio frequency (RF). The RF signal for mode locking is generated from a Fabry-Perot laser diode (FP-LD) under optical injection. The output frequency can be varied by adjusting the biasing current of the FP-LD. (Abstract shortened by UMI.)