Fig. 1. Schematic illustration of the MZI with the Ge implanted waveguides in both arms and the localized annealing process using a scanning laser.

Fig. 2. Optical microscope image of the Ge implanted waveguides on both arms of the MZI.

Fig. 3. Experimental setup for laser annealing (PBS, polarization beam splitter; BS, pellicle beam splitter; MO, microscope objective).

Fig. 4. Measured results (normalized optical transmissions) of the output ports of the (a) MZI device I and (b) MZI device II while changing the annealing length of the implanted waveguide. Calculated results were also fitted and plotted correspondingly. The 10× objective lens was used to anneal these samples.

Fig. 5. Measured results (normalized optical transmissions) of the output ports of the (a) MZI device III and (b) MZI device IV while changing the annealing length of the implanted waveguide. Calculated results were also fitted and plotted correspondingly. The 20× objective lens was used to achieve better position accuracy for laser annealing.