Tunable DBR laser with wide tuning range

Characteristics of a 1.55 mu m wavelength tunable DBR laser with three sections are described. The wavelength tuning range is investigated by changing the composition of the GaInAsP guide layer. The maximum change of the Bragg wavelength is nearly 10 nm at lambda /sub g/=1.38 mu m, and a continuous tuning range of 6.2 nm is achieved for lambda /sub g/=1.29 mu m.