Magneto-optic-acousto-optic joint coding method for single-spatial-mode coherent optical communication

Abstract

The invention relates to a magneto-optical acousto-optical combined encoding method for single space mode coherent light communication; the method comprises the following steps: according to a Heisenberg uncertainty principle of Stokes parameters, encoding signal polarization parameters of a single beam, and selecting the S1 parameter of the Stokes as a local oscillator light and the S2 or S3 parameter as an encoded signal; modulating amplitudes of the signals S2 and S3 with optical rotation effect of a magneto-optical modulator, realizing switchover between the encoded signals S2 and S3 with photo-elastic effect of an acousto-optical modulator, and combing with the acousto-optical and magneto-optical modulators to realize encoding the Stokes parameters; and the amplitudes of the coded signals are randomly selected via a random number generation circuit. The modulation encoding method disclosed by the invention has the advantages of simple structure, relatively rapid modulation rate, no high requirement of a modulation system on a driving circuit, and no need to use a complex polarization control algorithm, etc.

Description

technical field [0001] The invention relates to a magneto-optic, acousto-optic joint coding method for single-space-mode coherent optical communication. Background technique [0002] In coherent optical communication systems, the amplitude, phase, and polarization of coherent light are often used as the carrier of the signal to realize the modulation and encoding of the signal. In quantum communication, coherent states also play an important role. Quantum secure communication using single photons to realize quantum key distribution does not currently have an ideal single photon source, and pulsed lasers or chopper devices are usually required to obtain weakly coherent light with an average photon number of only a few photons. Not only that, the single-photon detectors required for communication based on single-photon quantum cryptography are harsh and expensive. The use of continuous variable coherent state quantum communication can avoid the above-mentioned difficulties a...

AI Technical Summary

Problems solved by technology

Therefore, the output polarization state of the magneto-optical modulator can only rotate on the equator of the Poincare sphere, and the range of polarization modulation is limited

In addition, the magneto-optical modulator generally uses a constant voltage source to drive the electromagnet to magnetize the magneto-optic medium, and the modulation rate is slow.

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