Abstract: A 1.3 ?m-band wavelength-tunable DBR laser in which a wavelength-tunable amount is extended is disclosed. The wavelength-tunable DBR laser according to an embodiment of the present invention is a wavelength-tunable DBR laser in which an active region having an optical gain and a DBR region including a diffraction grating are integrated monolithically and an oscillation wavelength is changed by injecting a current into the DBR region. At a boundary between a p-side clad layer and a core layer in the DBR region, an electron barrier layer being p-type doped and having a bandgap greater than in the p-side clad layer is further included. At a boundary between an n-side clad layer and the core layer in the DBR region, a hole barrier layer being n-type doped and having a bandgap greater than in the n-side clad layer is further included.