Optical communication with two-photon coherent states--Part I: Quantum-state propagation and quantum-noise

摘要: Recent theoretical work has shown that novel quantum states, called two-photon coherent states (TCS), have significant potential for improving free-space optical communications. The first part of a three-part study the communication theory TCS radiation is presented. issues quantum-field propagation and optimum quantum-state generation are addressed. In particular, analog classical paraxial diffraction quasimonochromatic scalar waves developed. This result, which describes arbitrary as boundary-value problem suitable system analysis, used to treat number transmitter optimization problems. It that, under near-field conditions, maximizes field-measurement signal-to-noise ratio among all states; performance exceeds conventional (coherent state) by factor N_{s} + 1 , where average signal photons (transmitter energy constraint). Under far-field it use local oscillator in receiver can, principle, attenuate noise equal loss channel, if appropriate spatial mode mixing can be achieved. These communcation results derived assuming field-quadrature measurement performed. II this study, photoemissive reception will considered; therein homodyne detection fields realize - to-noise I. III, relationships between general measurements explored. synthesis procedure obtained realizing described TCS.