Measurements on competition between carrier-induced and thermally-induced wavelength tuning in ridge waveguide DBR lasers

The tuning characteristics of ridge waveguide DBR lasers have been measured under CW and pulsed grating currents. Under CW grating current injection, a maximum tuning range of 2.5 nm was measured. This tuning range was extended to almost 7 nm under pulsed conditions. The increase in the tuning range is explained by the absence of thermal tuning mechanisms for pulsed grating currents and the dominance of thermal tuning in the ridge waveguide structure at large CW grating currents is explicitly shown.