Figure 5
From: Quantum encryption in phase space with displacement operators
Illustration of data b mapping to QAM modulations with QPSK and 16-QAM. On the one hand, each constellation point is expressed with I-component and Q-component of the modulated coherent state in the phase space. On the other hand, each constellation point represents a coherent state associated with a bit string. For QPSK, the constellation points represents 00, 01, 10, 11. For 16-QAM, the constellation points represents a 4-bit string