We demonstrate a high-speed silicon carrier-depletion Michelson interferometric (MI) modulator with a low on-chip insertion loss of 3 dB. The modulator features a compact size of <1 mm2 and a static high extinction ratio of >30 dB. The Vπ·Lπ of the MI modulator is 0.95–1.26 V·cm under a reverse bias of 1 to 8 V, indicating a high modulation efficiency. Experimental results show that a 4-level pulse amplitude modulation up to 20 Gbaud is achieved with a bit error rate of 6×10 3, and a 30 Gb/s binary phase-shift-keying modulation is realized with an error vector magnitude of 25.8%.