| 摘要 |
PURPOSE:To copy photon number information of a signal optical pulse to phase information of a probe optical pulse and to suppress the influence by quantum noise so that said information can be read out in a high S/N by using an output optical pulse of a degeneracy parametric amplifier as the probe optical pulse and allowing it to collide with the signal optical pulse. CONSTITUTION:Optical pulses 1-3 are made incident on an optical fiber in which there is a negative dispersion. Subsequently, the number of photons and a half- amplitude level of the optical pulses 1-3 are determined in advance so as to form an optical soliton, and by a wavelength dispersion, the signal optical pulse 3 is emitted from the optical fiber 5 in order of an emitted reference optical pulse 6, an emitted probe optical pulse 7 and an emitted signal optical pulse 8. By an optical switch 13, a reference optical pulse 14 and a probe optical pulse 15 are separated and a delay is supplied to the probe optical pulse 15 side, and by its delay, the probe optical pulse 15 and the reference optical pulse 14 interfere with each other by 50-50% on a half mirror 16. A differential synthesizing circuit 19 fetches a phase difference of the probe optical pulse 15 and the reference optical pulse 14 as a differential output. In such a way, photon number information of the signal optical pulse is copied to phase information of a probe light, and also, since a GAWBS noise is suppressed, an S/N is improved. |
