Steering nonlocality in high-speed telecommunication system without detection loophole

Nonlocal correlation represents the key feature of quantum mechanics, and is an exploitable resource in quantum information processing. However, the loophole issues and the associated applicability compromises hamper the practical applications. We report the first detection-loophole-free demonstration of steering nonlocality in a fully chip-fiber telecommunication system, with an ultra fast measurement switching rate (2.5~GHz). In this endeavor, we propose the phase-encoding measurement scheme to adapt the system to the GHz-level modulation rate. We design and fabricate a low-loss silicon chip for efficient entanglement generation, and come up with an asymmetric paradigm to mimic the measurement implementation at the steering party thus avoiding the phase-encoding loss. Consequently, we build a fiber-optic setup that can overcome the detection efficiency that is required by conclusive quantum steering with actively switched multiple measurement settings. Our setup presents an immediate platform for exploring applications based on steering nonlocality, especially for quantum communication.