Fig. 4: EDG measurements.

a Experimental setup. b Optical microscope view of the fabricated EDG. c–f Transmission spectra of wavelength scans at the eight channels under TE polarization and TM polarization. c Outputs from Ch. 1–4 with TE input. d Outputs from Ch. 1–4 with TM input. e Outputs from Ch. 5–8 with TE input. f Outputs from Ch. 5–8 with TM input.