An on-chip optical switch based on an echelle grating and a phase tuning element is described herein. The phase tuning element may change a refractive index of the material through which an optical signal propagates, thereby causing a change in the angle of propagation of the optical signal. By dynamically tuning the phase change element, the refractive index change may be controlled such that the deviation of the optical signal causes the optical signal to be focused on a particular coupling waveguide out of an array of coupling waveguides. The echelle grating with the active phase change element form a configurable optical switch capable of switching an optical signal between two or more coupling waveguides, that may be respectively connected to different optical signal processing pathways.