Analysis of large-signal dynamic characteristics of 10-Gb/s tunable distributed Bragg reflector lasers integrated with electroabsorption modulator and semiconductor optical amplifier based on the time-dependent transfer matrix method

We investigate large-signal dynamic characteristics of tunable distributed Bragg reflector (DBR) lasers with different structures. Because of high chirp and complex structures of tunable DBR lasers, it is difficult to accurately analyze large signal chirp and output pulse shapes with analytical models. Therefore, we apply a numerical model based on the time-dependent transfer matrix method to tunable DBR lasers integrated with electroabsorption modulator (EAM) and semiconductor optical amplifier (SOA). Using this model, we find a suitable α-parameter range in the Bragg grating section (α/sub Bragg/-parameter) that produces the tolerable wavelength chirp while maintaining a proper tuning range. To employ the tunable lasers in wavelength division multiplexed networks and improve flexibility of the networks, the tunable lasers should have high output power and low wavelength chirp. According to our simulation results, the EAM section had better be located in between SOA and DBR laser sections to obtain high output power and low wavelength chirp.

I. Introduction

IN FUTURE wavelength-routed wavelength division multiplexed (WDM) networks, it is important for optical transmitters to have high output power, high transmission capacity, and wavelength-tunable functionality. There are two major methods to achieve wavelength-tunable functionality using laser arrays [1], [2] and tunable lasers [3]–[9]. The tunable lasers are more attractive than the laser arrays due to their compactness and simple process. Recent research has focused on a few types of the tunable lasers: distributed Bragg reflector (DBR) lasers [4], [5], sampled or superstructure-grating DBR lasers [6], [7], and vertical-coupler sampled-reflector lasers [8]. Among them, the DBR lasers are interesting due to their simple structure, proper tuning range, and high reliability.