Record tuning range of a 1.55 μm DBR laser realized by selective area growth

Wavelength tunable lasers are key devices for WDM optical communication systems. Several approaches have been used to realize these components such as butt-coupling, vertical coupling or Selective Area Growth (SAG). We used the latter owing to its simplicity for achieving, in only one epitaxial step, regions of different transition energy and high optical coupling factor. An optimized guide structure allowed us to reach a tuning range of 7 nm, which is to the best of our knowledge a record with this approach. The use of strained MQWs allows the active-passive wavelength detuning to be reduced down to about 80 nm which results in a quite stable output power (+1 dB) during tuning of the laser diode