Abstract
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.
Highlights
Tunable semiconductor lasers are indispensable components in numerous applications crossing multi-disciplinary fields, for instance, sensing, process control, and optical access networks in particular [1]
Using the set of rate equations, the laser optical power and light-emission characteristics of the monolithic two-section InAs/InP Qdash laser diode is analyzed for wavelength tunability assuming all carriers are available in the separate confinement heterostructure (SCH) laser and injected into the wetting layer (WL) layer, i.e., ηi = 1 and τS = ∞
The considered InAs/InP Qdash laser devices consists of N lyr = 4 layer of dashes with corresponding mean height, width and cross-section density h D h = 1.5 nm, w D h = 20 nm and A D h = 7.9 × 10−13cm2, and SCH (WL) thickness w SCH = 100 nm (w WL = 5 nm)
Summary
Tunable semiconductor lasers are indispensable components in numerous applications crossing multi-disciplinary fields, for instance, sensing, process control, and optical access networks in particular [1]. In the past few years, InAs/InP quantum-dash (Qdash) nanostructure active region-based amplifiers and lasers have demonstrated superior performances, compared to their Qwell and Qdot counterparts [10], thanks to their mixed quantum-wire and Qdot feature, and controlled emission tuning spanning from ∼1400–1900 nm [11]. With these niche features, Qdash devices, and lasers in particular, are taking center stage in potential deployment in WDM systems that are expected to exhibit extended bandwidth up to L– and U – band, in generation access networks [2]. Besides large tunability, extended lasing bandwidth was observed from the devices with large absorber section lengths and large active region inhomogeneity
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