Slotted tunable laser with monolithic integrated mode coupler

We present a tunable laser based on partially reflective slots etched into the active ridge of a laser the output of which is monolithically coupled into a lower waveguide using a tapered coupler. The laser demonstrates a tuning range of 2.8 THz covering 8 channels separated by 400 GHz. The coupling efficiency to the lower waveguide is up to 90%. This approach requires no epitaxial re-growth making it suitable for low cost photonic integration with additional functional devices such as an integrated IQ modulator.