Chip-Based Quantum Key Distribution Transceiver with Polarization Splitter-Rotator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing quantum key distribution (QKD) systems using polarization encoding methods face challenges due to size and cost limitations, as well as polarization dependence in chip-based implementations, which affect the reliability and efficiency of quantum key distribution.
Innovation Solution
A transmitting and receiving device for quantum key distribution based on a chip is designed to use a single light source, minimizing size, and is configured to allow only a single polarization to pass through, enhancing performance. The device includes a base with a light entrance and exit, beam splitters, phase modulators, and a polarization splitter-rotator, which modulates and combines optical signals to ensure only one polarization is transmitted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polarization encoding method is used in QKD systems, then communication security is improved, but device size and cost increase
Solution Approach 1:
The patent combines multiple optical paths (first and second optical paths) into a single integrated chip structure with shared components. The beam splitter, phase modulators, and polarization splitter-rotator are merged into one compact device, reducing overall size while maintaining the polarization encoding capability for secure communication.
Solution Approach 2:
The single chip structure performs multiple functions: it acts as a beam splitter, phase modulator, and polarization splitter-rotator simultaneously. This multi-functional integration allows the device to maintain complex polarization encoding operations while minimizing device footprint and component count.
2Reliability
If multiple light sources are used in QKD systems, then communication performance is improved, but device size and manufacturing complexity increase
Solution Approach 1:
The patent integrates both the first and second optical paths onto a single chip, combining multiple light sources and their associated components into one unified device. This integration simplifies manufacturing by reducing the number of separate components that need to be assembled and aligned, while maintaining the performance benefits of multiple light sources.
3Adaptability or versatility
If polarization-dependent components are used in chip-based QKD, then encoding capability is improved, but reliability decreases due to polarization dependence
Solution Approach 1:
The patent introduces a polarization splitter-rotator as an intermediary component that actively manages polarization states. This component separates and rotates polarization directions to ensure that only the desired polarization passes through each optical path, eliminating the reliability issues caused by unwanted polarization dependence while preserving the encoding capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution miniaturizes the size of QKD devices, improves performance by ensuring only one polarization passes through, and simplifies device fabrication by allowing identical internal configurations for both transmitting and receiving devices.
Implementation Method 1
a first beam splitter positioned inside the base and disposed in a first optical path extending from the light entrance, reflecting part of an optical signal incident through the first optical path on a second optical path and allowing a remaining portion to be transmitted into a third optical path
Implementation Method 2
a first modulator positioned inside the base to modulate a phase of an optical signal reflected from the first beam splitter and incident on the second optical path
Implementation Method 3
a polarization splitter-rotator positioned inside the base, and transmitting, with a time difference, an optical signal incident from the second modulator and an optical signal incident from the first modulator to the one light exit
Data Source
AI summary
A transmitting and receiving device for quantum key distribution based on a chip comprising a base including one light entrance and exit; a first beam splitter, reflecting part of an optical signal incident through a first optical path on a second optical path and transmit a remaining part of the optical signal to a third optical path; a first modulator modulating a phase of an optical signal reflected from the first beam splitter and incident on the second optical path; a second modulator delaying the optical signal transmitted from the first beam splitter and incident on the third optical path for a predetermined period of time and modulate a phase of the optical signal; and a polarization splitter-rotator transmitting an optical signal incident from the second modulator, with a time difference relative to an optical signal incident from the first modulator, to the one light exit.