Modeling of widely tunable V-cavity semiconductor laser using time-domain traveling-wave method

Abstract

We investigate the static and dynamic characteristics of the widely tunable V-cavity semiconductor laser using the time-domain traveling-wave method. The theoretical model is presented. The simulation results are compared with experimental data for an all-active V-cavity laser, and good agreements are obtained. To improve the device performance, a new device structure with passive tuning waveguides is designed. The numerical results show that 21 channels can be achieved by single electrode tuning using carrier injection effect with two cavities of 420 and 440 μm long. Dynamic wavelength switching between different channels is simulated. Mode competition is observed during the transient and the switching delay time varies from 3 to 18.5 ns for different switching paths. A simple algorithm for quasi-continuous tuning is developed for the first time by varying the injection currents on the channel selector electrode and the fine-tuning electrode synchronously. A quasi-continuous tuning of 16.8 nm is achieved with a current variation of less than 20 mA on each electrode. For direct modulation characteristics, small signal response simulation is carried out by an impulse current injection with a fast Fourier transform algorithm, and a 3 dB bandwidth of 7 GHz is obtained when biased at 100 mA. Moreover, 2.5 and 10 Gb/s direct intensity modulation are also demonstrated. The simulation results show great potential for the compact and low-cost tunable laser to be used for wavelength-agile access and data center networks, as well as biomedical applications.