On-chip encoder

Abstract

An on-chip encoder comprises: an input waveguide (100); a 1 * 2 light beam splitter (200) used for splitting the received signal light into two beams of signal light respectively; a signal light switch (300) used for realizing passing and blocking of the signal light; a phase bias modulator (400) used for adjusting the phases of the four beams of signal light; 1 * 2 light beam combiners (500), comprising a first light beam combiner (501) and a second light beam combiner (502); a polarization rotation beam combiner (600) used for receiving the two beams of signal light output by the 1 * 2 lightbeam combiner (500) and rotating one of the two beams of signal light, so that the polarization direction of the rotated signal light is orthogonal to the polarization direction of the other beam ofsignal light, and the rotated signal light and the other beam of signal light are combined into one beam; and output waveguide (700). Four kinds of polarization state signal light are generated through logic combination of the signal light switch (300), the phase bias modulator (400) and the like, and the modulation requirement of polarization BB84 protocol quantum key distribution is exactly met.

Description

technical field [0001] The invention relates to the technical field of quantum communication and integrated optics, in particular to an on-chip encoder. Background technique [0002] The currently recognized quantum key distribution devices are mainly based on traditional discrete optical prisms or fiber optic devices, which are bulky, difficult to integrate, and costly, which is not conducive to large-scale commercialization. With the development of silicon-based photonics, the functions of discrete optical devices can gradually be realized on-chip, which facilitates integration. At the same time, using mature silicon device processing platforms, large-scale and low-cost mass production can be realized. So people began to try to integrate the devices and subsystems required by the quantum key distribution device on the chip. For the polarization BB84 protocol quantum key distribution, the technical core is to prepare different polarization states of light. However, for sili...

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Problems solved by technology

So people began to try to integrate the devices and subsystems required by the quantum key distribution device on the chip. For the polarization BB84 protocol quantum key distribution, the technical core is to prepare different polarization states of light. However, for silicon materials, because there is no The linear electro-optic effect achieves phase delay by modulating the refractive index, mainly relying on the thermo-optic effect and the plasma dispersion effect. The thermo-optic effect is slow and it is difficult to achieve high-speed modulation, while the plasma dispersion effect is fast, but the modulation efficiency is relatively low. , leading to phase delay difficulties and introducing additional losses, making it difficult to implement a high-speed on-chip polarization encoder

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