Dual-Junction Monolithically Integrated Monitoring Photodiode With a Two-Stage 18 GHz 18 pA/√Hz TIA in 22-nm FDSOI

We present a monolithically integrated (MI) dualjunction monitoring photodiode (PD) and transimpedance amplifier (TIA). The photocurrent originates from the deep Nwell (DNW)/P-type substrate (PSUB) $({\lt }5~ \mathrm {GHz})$ and the P-Well $(\mathrm {PW}) / \mathrm {DNW}({\gt }1~ \mathrm {GHz})$ junctions. The presented combination of bulk PD and 22 nm fully-depleted silicon-on-insulator (FDSOI) TIA (18-GHz bandwidth (BW), $17.8 ~\mathrm {pA} / \sqrt {\mathrm {Hz}}$ noise level) advances the state-of-the-art in MI high-speed optical monitoring and reduces the inherent tradeoff in MI solutions regarding PD (responsivity & BW) and RF circuitry $(f_{t})$ performance.