| 摘要 |
<p>The invention combines the differential-phase technique and the frequency-modulation technique such that the emitter (15) uses two oscillators (18, 18a), the phase of which is modulated, taking values of 0 or pi by the use of phase shifters (19). The phase-modulated electric signal is applied to an electro-optic modulator (17, 17a) in order to perform frequency modulation on an optical source that emits pulses with a photon. The signal is received in a receiver (16) which, by means of an electro-optic modulator (22, 22a) to which a frequency with phase shift 0 is applied, produces an interference between two optical frequencies, which makes it possible to detect the frequency in which the photon is received in order to obtain the bit sent in accordance with the phase selected by the emitter (16). The receiver sends the frequency in which the detection took place to the emitter, said emitter detecting the bit detected by the receiver.</p> |
