Semiconductor laser incorporating a short two-dimensional grating

A device has been demonstrated which for the first time incorporates a short two-dimensional grating in the ridge of a ridge-waveguide semiconductor laser. The device used for this work is a standard Fabry-Perot ridge-waveguide laser diode operating at 1.3 μm. The active layer contains seven InGaAsP quantum wells. By positioning the grating in the ridge of the laser there is a strong interaction with the lasing mode and only a short grating length is required to dramatically alter the performance of the laser. The output spectrum of the device shows it is lasing on a single longitudinal mode at a considerably shorter wavelength than before the grating was incorporated. Additional structure is observed from the grating and the temperature dependence of the lasing mode is reduced to that expected from a distributed-feedback semiconductor laser. This shows the dominance of the grating in determining the laser characteristics. Incorporating structures into the cavity in this way may allow enhanced functionality in future devices.