Fig. 1. (a) Top-view micrograph of the photonic chip showing the micro-ring resonators and the grating couplers; (b) photograph of the packaged photonic chip; (c) block diagram showing the in situ measurement setup. EDFA, erbium-doped fiber amplifier; GC, grating coupler; Opt. switch, optical switch; DUT, device under test. (d) Normalized transmittance spectra of a micro-ring resonator under test for both TE- and TM-polarized modes.

Fig. 2. (a) Insertion loss change of the fiber-packaged chip during in situ irradiation: here the error bars (shaded regions) are defined as the device-to-device variations on the same chip; (b) resonance shift due to gamma irradiation; the three spectra correspond to 0, 3.6 Mrad, and 8.4 Mrad radiation doses, respectively; (c) extracting material index changes from device measurements following protocols described in the text. The insets show TE- and TM-polarized waveguide mode profiles for SiC waveguides; (d) extracting material loss change from device measurement.

Fig. 3. In situ measured changes of (a) refractive indices and (b) optical losses in SiC and SiO2 induced by gamma ray irradiation; (c) TE mode intensity profile of the radiation-hard SiC waveguide device design; (d) projected TE-mode effective index change of the design in (c) based on measurement data in (a). The shaded regions in (a), (b), and (d) denote standard deviations of data taken on multiple devices on the same chip.

Fig. 4. Post-irradiation relaxation of (a) refractive indices and (b) optical losses in SiC and SiO2. The shaded regions in (b) denote standard deviations of data taken on multiple devices on the same chip.

Fig. 5. SIMS elemental depth profiles of (a) as-deposited and (b) irradiated a-SiC films.