Demonstration of 1.3um wavelength range super structure grating DBR laser with wide wavelength tuning range of over 30 nm by introducing carrier confinement layers

In this study, the 1.3 μm wavelength range super structure grating (SSG-) distributed Bragg reflector (DBR) laser was experimentally demonstrated for the first time. The use of 1.3 μm wavelength range tunable DBR lasers has been barely reported because of their small refractive index change compared with that of the 1.55-μm wavelength range, although 1.3 μm is a major wavelength range for optical communication. One reason is that increasing the carrier concentration in the InGaAsP core layer in the DBR sections is difficult. This is because the bandgap energy of the core layer for 1.3-μm wavelength range lasers should be relatively large compared with that of 1.55-μm wavelength range lasers, and it reduces the band offset between core and InP claddings. To efficiently trap the carrier inside the core layer, we introduced InAlAs carrier confinement layers (CCLs) to both boundaries between the core layer and cladding layers. As a result, the 1.3 μm wavelength range SSG-DBR laser was successfully demonstrated with a 4.9-nm quasi-continuous wavelength tuning range by using the single SSG-modes. Furthermore, the total wavelength tuning range of 31 nm and stable single mode operation for the entire tuning range were achieved. The introduced CCLs significantly enhanced the refractive index change due to the carrier-plasma effect and thus we can successfully demonstrate wide range tuning of the 1.3-μm wavelength range SSG-DBR laser.