Over 5.8-nm continuous wavelength tuning of 1.5-μm wavelength tunable D8R laser

Wavelength tunable single-longitudinal-mode semiconductor lasers are attractive light sources for future high-density WDM and coherent optical transmission systems. Among many kinds of wavelength tunable semiconductor laser, a Bragg wavelength tunable distributed Bragg reflector (DBR) laser is one of the most suitable light sources because of its large range tuning ability. However, only discrete tuning or <1-nm continuous tuning has been reported.1–3 Here 1.5-μm wavelength tunable DBR lasers with large continuous tuning ranges are reported for the first time, we believe. Wavelength tuning was performed by controlling the injection currents Into the DBR and phase control (PC) regions, which changed the refractive indices of these regions.4