High-Speed DD Transmission Using a Silicon Receiver Co-Integrated with a 28-nm CMOS Gain-Tunable Fully-Differential TIA

We report >100-Gb/s direct-detection (DD) transmission using an integrated silicon optical receiver, which comprised a fully-differential 28-nm complementary metal-oxide-semiconductor (CMOS) transimpedance amplifier (TIA) wire-bonded to a Silicon-Germanium (SiGe) balanced photodiode (PD). The fully-differential TIA architecture enabled significant bit-error-rate (BER) and signal-To-noise ratio improvements over a single-output TIA design when introducing it to the DD transmission. We experimentally validated its effectiveness in both back-To-back (B2B) and 2-km long standard single-mode fibre (SSMF) links using 50/100-Gb/s signals, including Nyquist on-off keying (OOK), Nyquist 4-Ary pulse amplitude modulation (PAM4), uniformly-loaded DD optical orthogonal frequency division multiplexing (DDO-OFDM) and adaptively-loaded DDO-OFDM. Furthermore, we demonstrate that the integrated optical receiver was capable of balancing the trade-off between its electrical bandwidth and transimpedance gain by simply adjusting a voltage supply to the TIA. Without the need for optical amplification and while keeping the BERs below the 7% forward error correction limit, up to 173.22-Gb/s and 139.86-Gb/s adaptively-loaded DDO-OFDM transmission was achieved for B2B and 2-km transmission, respectively. The demonstrated results highlight the potential of the integrated silicon optical receiver, fabricated using the standard CMOS process for high-speed and short-reach optical interconnects.