Tunable two-section InAs/InP quantum-dash laser: Numerical modeling and analysis

We report a multi-population rate-equation based numerical model for investigating broadband two-section InAs/InP quantum-dash laser. The model incorporates the quantum-wire-like nature of dashes along with the inhomogeneous broadening of the active region. Numerical results of light power-injection current and spectral characteristics at various absorber section lengths are shown to be in good agreement with the experimental results. Moreover, inhomogeneous broadening displayed a pivotal role in achieving large tunability from the monolithic two-section devices, in addition to demonstrating an extended lasing bandwidth. A blue-shift tuning window of 41.7 nm and bandwidth improvement of 18.5 nm is exhibited by 1000 μm cavity length device with largest active region inhomogeneity. In general, shorter 800-1000 μm and longer 2000 μm cavity length devices showed large wavelength tunability of 49 and 65 nm, respectively, in 1560-1640 nm wavelength region. This comprehensive analysis would enable design optimization of the tunable two-section devices that are considered potential key components in optical access networks.