This work discusses a large output-swing 224-Gb/s PAM4 optical receiver with multiple peaking techniques in 130-nm SiGe BiCMOS. The receiver consists of a trans-impedance amplifier (TIA), a continuous-time linear equalizer (CTLE), and a 2-stage single-to-differential converter (S2D). An RC parallel structure is implemented in the TIA, effectively broadening the bandwidth. Moreover, multiple peaking techniques, including RC emitter degeneration, shunt-inductive peaking and T-coil peaking, are adopted to extend the bandwidth to 61 GHz. To minimize the output mismatch, inductors in S2D are typically chosen in different magnitude. Consuming 96.85-mW power, the designed system achieves a differential conversion gain of 58 dBΩ, while the imbalances in amplitude and phase are limited to 0.2 dB and 1.6°, respectively.