Experimental demonstration of a quantum receiver beating the standard quantum limit at the telecom wavelength

Understand

Discrimination of coherent states beyond the standard quantum limit (SQL) is an important tasknot only for quantum information processing but also for optical coherent communication.

• In orderto optimize long distance optical fiber networks, it is of practical importance to develop a quantumreceiver beating the SQL and approaching the quantum bound at telecom wavelength.
• In this paper,we experimentally demonstrate a receiver beating the conventional SQL at telecom wavelength.
• Ourreceiver is composed of a displacement operation, a single photon counter and a real time adaptivefeedback operation.