Fig. 1. Designed waveguide. (a) Cross section; (b) simulated field distribution of TM polarization

Fig. 2. Desired far field distribution of the designed and the detailed structure of the auxiliary waveguides. (a) Desired waveguide array with auxiliary waveguides (expected sinc field distribution in the output of a single array waveguide and the flat-topped field distribution in the output image plane are indicated in the figure); (b) detailed structure of auxiliary waveguides

Fig. 3. Field distribution with the conventional design and optimal design at the image plane

Fig. 4. Microscope pictures of the fabricated AWGR. (a) AWGR with auxiliary waveguides; (b) AWGR without auxiliary waveguides

Fig. 5. Pictures of the fabricated waveguides. (a) Microscope picture of the connection area of the waveguide array with auxiliary waveguides and the output FPR; (b) SEM image of the SiON waveguide cross section

Fig. 6. Transmission spectra of the designed 7×7 AWGR with auxiliary waveguides. (a) Edge input channel; (b) central input channel

Fig. 7. Transmission spectra of the conventional 7×7 AWGR. (a) Edge input channel; (b) central input channel

Fig. 8. Insertion loss for all output channels of the two 7×7 AWGRs. (a) Edge input channel; (b) central input channel

Fig. 9. Transmission spectra of each input channel when light is input backward

Fig. 10. Insertion loss comparation when light is input forward and backward