Chirp-Compensated DBR Lasers for TWDM-PON Applications

We propose a novel chirp compensation scheme for directly modulated three- section distributed Bragg reflector (3s-DBR) lasers in applications of the time- and wavelength-division multiplexed passive optical network systems. The frequency chirp of 3s-DBR lasers induced by direct modulation is investigated through extensive numerical simulations based on the time-domain travel-wave model. To overcome the signal dis- tortions resulting from the frequency chirp due to direct modulation, we extend on our novel idea of frequency chirp compensation technology with inherent characteristics of DBR-type tunable lasers. Q factors and extinction ratio for different system transmission lengths are analyzed and compared. Large dispersion tolerance of the system is achieved by using the chirp compensation scheme.