Fig. 1. Schematic diagram of the Ge-free MRR APD.

Fig. 2. (a) Measured normalized transmission spectrum at zero bias voltage. (b) Schematic of an MRR device. (c) Simulated coupling coefficient with the 1310 nm TE mode light [38].

Fig. 3. Simulated (a) electric field and (b) energy band diagrams of the Si PN junction at different bias voltages.

Fig. 4. Measured 2D colormaps of responsivity versus reverse-bias voltage and wavelength with bus WG power at (a) −4.5  dBm, (b) 1.5 dBm, and (c) 6.5 dBm.

Fig. 5. Measured (a) total and dark currents, (b) wavelength, and (c) responsivity at resonance with bus WG power at −4.5, 1.5, and 6.5 dBm, respectively.

Fig. 6. Measured and fitted photocurrent and responsivity versus bus WG power at reverse bias of (a), (b) −4  V and (c), (d) −6.4  V.

Fig. 7. (a) Simulated avalanche gain versus bias voltage at 0.1 mW. (b) Fitted avalanche gain versus optical power at −6.4  V.

Fig. 8. (a) Measured S11 response of the MRR APD at bias voltage of −3  V, −6  V, and −6.4  V. (b) Measured and fitted S11, (c) equivalent circuit, and (d) frequency response of the equivalent circuit at bias voltage of −6  V.

Fig. 9. (a) Measured O-E S21 response at resonance. Measured eye diagrams of (b) 80 Gb/s NRZ and (c) 100 Gb/s PAM4 modulations with 6.5 dBm optical power in the bus WG at bias voltage of −6.4  V.

Fig. 10. Calculated responsivity of the all-Si straight waveguide with 1 mW input optical power at −6.4  V.