On-chip high-speed polarization control encoder applied to distribution of quantum keys

Abstract

The invention discloses a high-speed polarization control encoder on a silicon chip applied to distribution of quantum keys. The encoder comprises a polarization beam splitting rotator with an input end connected with an input waveguide; a first 1*4 beam splitter with an input end connected with a first output port of the polarization beam splitting rotator; a first phase delayer, a second phase delayer, a third phase delayer and a fourth phase delayer, wherein one end of each of the four phase delayers is connected with an output end of the 1*4 beam splitter, while the other end is connected with a first variable optical attenuator; a second 1*4 beam combiner with an input end connected with the other ends of the first variable optical attenuators behind the first 1*4 beam splitter; and a polarization beam combiner with an first input port connected with the an output end of a second 1*4 beam combiner, and an second input port connected with a second output port of the polarization beam splitting rotator via a second variable optical attenuator.

Description

technical field [0001] The invention relates to the technical field of quantum communication and integrated optics, in particular to an on-chip high-speed polarization control encoder required for quantum key distribution. Background technique [0002] The current Internet information security encryption method is called "public key" cryptography system. Its principle is to generate a public key that spreads on the network and a private key that stays inside the computer through an encryption algorithm. The two keys must match Use to achieve a complete encryption and decryption process. The encryption standard used in modern cryptography is the RSA algorithm born in the 1970s, which uses the prime factorization of large numbers to decompose difficult calculations to ensure the security of keys. With the continuous improvement of computing power, especially the concept of quantum computer, the security of RSA has been challenged. Quantum cryptography is the product of the c...

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Problems solved by technology

The core polarization control encoder needs to prepare different polarization states of light. However, because the silicon material has no linear electro-optic effect, the modulation of the refractive index to achieve phase delay mainly relies on the thermo-optic effect and the plasma dispersion effect. The thermo-optic effect is slow and difficult to realize. High-speed modulation, the plasma dispersion effect is relatively weak, it is difficult to achieve a large phase delay, and will introduce additional loss at the same time, so it is difficult to realize a high-speed on-chip polarization control encoder

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