Modulation Bandwidth and Linewidth Enhancement Factor of High-Speed 1.55-$\mu$ m Quantum-Dash Lasers

InAs-InGaAlAs-InP quantum-dash lasers have been fabricated showing continuous-wave operation up to 100degC with a characteristic temperature of 88 K between 25degC and 85degC and output powers above 27 mW at room temperature (RT). The small-signal modulation bandwidth of 10 GHz at RT amounts still to 4 GHz at 85degC. The linewidth enhancement factor above threshold is evaluated by means of the frequency-modulation/amplitude-modulation method in dependence on modulation frequency and drive current, exhibiting a value of 2.5 slightly above threshold.