Configurations for a tunable Echelle grating are disclosed. The tunable Echelle grating may include an output waveguide centered in a waveguide array, with input waveguides on both sides of the output waveguide. A metal tuning pad may be located over the slab waveguide and may be heated to induce a temperature change in the slab waveguide. By increasing the temperature of the propagation region of the slab waveguide, the index of refraction may shift, thus causing the peak wavelength of the channel to shift. This may result in an optical component capable of multiplexing multiple light sources in an energy efficient manner while maintaining a small form factor.