QPSK coherent state discrimination via a hybrid receiver

We propose and experimentally demonstrate a near-optimal discrimination scheme for the quadrature phase shift keying protocol (QPSK). We show in theory that the performance of our hybrid scheme is superior to the standard scheme heterodyne detection for all signal amplitudes and underpin the predictions with our experimental results. Furthermore, our scheme provides the hitherto best performance in the domain of highly attenuated signals. The discrimination is composed of a quadrature measurement, a conditional displacement and a threshold detector. PACS numbers: 03.67.Hk, 03.65.Ta, 42.50.Ex ar X iv :1 20 4. 08 88 v2 [ qu an tph ] 2 6 Ju n 20 12 QPSK coherent state discrimination via a hybrid receiver 2

[1]  Julius Goldhar,et al.  M-ary-state phase-shift-keying discrimination below the homodyne limit , 2011 .

[2]  Masahide Sasaki,et al.  Quantum receiver beyond the standard quantum limit of coherent optical communication. , 2011, Physical review letters.

[3]  Antti Toskala,et al.  WCDMA for UMTS: HSPA Evolution and LTE , 2010 .

[4]  S. Inoue,et al.  Sub-shot-noise-limit discrimination of on-off keyed coherent signals via a quantum receiver with a superconducting transition edge sensor. , 2010, Optics express.

[5]  Masahiro Takeoka,et al.  Discrimination of binary coherent states using a homodyne detector and a photon number resolving detector , 2010, 1002.0232.

[6]  Masahiro Takeoka,et al.  Demonstration of coherent-state discrimination using a displacement-controlled photon-number-resolving detector. , 2009, Physical review letters.

[7]  G. Leuchs,et al.  Coherent state quantum key distribution with multi letter phase-shift keying , 2009, 0902.1895.

[8]  Anthony Leverrier,et al.  Unconditional security proof of long-distance continuous-variable quantum key distribution with discrete modulation. , 2008, Physical review letters.

[9]  Masahide Sasaki,et al.  Demonstration of near-optimal discrimination of optical coherent states. , 2008, Physical review letters.

[10]  Masahide Sasaki,et al.  Discrimination of the binary coherent signal: Gaussian-operation limit and simple non-Gaussian near-optimal receivers , 2007, 0706.1038.

[11]  Robert L. Cook,et al.  Optical coherent state discrimination using a closed-loop quantum measurement , 2007, Nature.

[12]  K. Willcox,et al.  Research Laboratory of Electronics , 2005 .

[13]  Gerd Leuchs,et al.  Continuous-variable quantum key distribution using polarization encoding and post selection , 2004, quant-ph/0403064.

[14]  S. Lloyd,et al.  Classical capacity of the lossy bosonic channel: the exact solution. , 2003, Physical review letters.

[15]  S. Olivares,et al.  Binary optical communication in single-mode and entangled quantum noisy channels , 2003, quant-ph/0309096.

[16]  Ban,et al.  Derivation and physical interpretation of the optimum detection operators for coherent-state signals. , 1996, Physical review. A, Atomic, molecular, and optical physics.

[17]  Charles H. Bennett,et al.  Quantum cryptography using any two nonorthogonal states. , 1992, Physical review letters.