A high-speed receiver optical subassembly (ROSA) based on silica hybrid-integrated technology for 400 G Ethernet applications is designed and manufactured. It consists of an eight-channel-arrayed waveguide grating (AWG) with a 2% refractive index difference, two 4-channel InP-based waveguide photodetector (PD) array chips, eight lenses for enhancing the coupling between AWG and PDs, two 4-channel trans-impedance amplifier array chips, and an eight-channel high-frequency flexible printed circuit. All the channels of the ROSA have achieved 3 dB bandwidths of above 27.05 GHz, and receiver sensitivities of below −8.5 dBm, supporting a receiving rate of 8×53 Gbps.