Quantum key distribution method and cascade modulator system

摘要

I discloses a method and (20) [challenge] QKD system cascade modulator system (10). [SOLUTION] modulator system has a (M2 and M1) of the two modulators connected optically in series. Parallel shift register (50), to generate voltage (ie binary) 2 bits (L1, L2). These voltage levels, to produce a (V1, V2) weighted voltages are adjusted respectively by (30-2 and 30-1) voltage regulator, to drive the modulator. Electrical delay element to synchronize the optical delay between the modulator (40), to provide the timing of the modulator (gating). Net modulation is applied to the (60) the optical signal (M _NET) is the sum of the modulation imparted by the modulator. Modulator system provides a possible net modulation of four on the basis of only the binary signal voltage. Thus, as compared with the case of using the voltage signal of the 4-level driving a single modulator, the modulation in the optical system and associated QKD system is more rapidly and efficiently. [Selection Figure Figure 2