Optical Path System for Quantum Communication Bypassing Interference
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Solution Overview
Problem
Conventional optical path systems for quantum communication experience series mode interference due to electro-optical modulators, which disrupts the transmission of optical signals in two-way quantum communication systems.
Innovation Solution
The optical path system incorporates a light source module, intensity and polarization modulation module, polarization maintaining interference ring, phase and intensity modulation module, isolators, beam splitters, Faraday rotators, and single photon detectors to perform intensity, polarization, and phase modulations, ensuring unidirectional signal transmission and reducing interference by bypassing the phase and intensity modulation module at the receiving end.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electro-optical modulators are used in conventional optical path systems, then modulation function is achieved, but series mode interference occurs in the optical signal circuit
Solution Approach 1:
The patent extracts and removes the electro-optical modulator from the optical path system, replacing it with a direct optical modulation approach using optical switches and beam splitters. This eliminates the source of series mode interference while preserving the modulation capability through alternative optical means.
Solution Approach 2:
The patent introduces an intermediary optical switching mechanism consisting of beam splitters and optical switches that mediates the signal transmission. This intermediary system achieves modulation without requiring electro-optical modulators, thereby avoiding series mode interference while maintaining the desired modulation function.
2Adaptability or versatility
If optical signal returns along original path for decoding, then two-way communication is enabled, but series mode interference disrupts transmission
Solution Approach 1:
The patent segments the optical path into distinct forward and return paths using beam splitters and optical switches. The return path is separated from the forward transmission path, allowing independent optimization of each path and preventing interference between bidirectional signals while maintaining two-way communication capability.
Solution Approach 2:
The patent introduces asymmetric path configuration where the return path is deliberately designed to be separate from the forward path. This asymmetric design prevents the series mode interference that would occur if the paths were symmetric and overlapping, thereby improving transmission reliability while preserving two-way communication.
3Device complexity
If conventional optical path configuration is used, then system simplicity is maintained, but modulation speed is limited
Solution Approach 1:
The patent replaces the conventional electro-optical modulation mechanism with a purely optical switching and beam splitting system. This substitution eliminates the speed limitations inherent in electro-optical conversion and enables faster modulation speeds while maintaining relatively simple system configuration through the use of standard optical components.
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
This configuration effectively reduces series mode interference, enhances modulation speed, and stabilizes the quantum communication system by allowing phase codes to be decoded accurately at the receiving end, improving the overall performance and accuracy of quantum communication.
Implementation Method 1
a 90-degree Faraday rotator mirror
Implementation Method 2
a beam splitter, a second polarization beam splitter
Implementation Method 3
a first isolator, a second isolator
Implementation Method 4
a polarization maintaining interference ring
Data Source
AI summary
Disclosed are an optical path system for quantum communication and a quantum communication method. The optical path system for quantum communication includes a light source module, an intensity and polarization modulation module, a polarization maintaining interference ring, a phase and intensity modulation module, a first isolator, a first polarization beam splitter, a second isolator, a beam splitter, a second polarization beam splitter, a second phase modulator, and a 90-degree Faraday rotator mirror. An optical signal may pass through a first polarization beam splitter, bypass a phase and intensity modulation module, and directly reach a polarization maintaining interference ring, thereby solving a problem of series mode interference in an optical signal circuit, and greatly improving a modulation speed of the circuit.