Separation Filter with Fiber Bragg Gratings for Quantum Signal Isolation
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Solution Overview
Problem
Existing quantum cryptographic communication systems face interference and noise issues due to significant signal intensity disparity between quantum and amplified optical signals, leading to reduced transmission distance and increased quantum bit error rates.
Innovation Solution
A separation filter utilizing optical circulators, fiber Bragg gratings, and angle-cleaved fibers to efficiently separate quantum signals from amplified optical signals, minimizing noise components like ASE and Raman scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If WDM technology is used to integrate quantum signals with amplified optical signals for transmission, then transmission distance and capacity are improved, but signal interference and noise increase due to significant signal intensity disparity
Solution Approach 1:
The patent extracts and removes the harmful noise components (ASE noise, Raman scattering, four-wave mixing) from the optical signal through optical filtering techniques. By separating the quantum signal from the amplified optical signal and removing the noise components, the system maintains the benefits of long-distance transmission while eliminating the harmful interference effects that would otherwise degrade quantum key distribution performance.
Solution Approach 2:
The patent introduces an intermediary filtering system between the optical amplifier and the quantum signal detection. This intermediary component (optical filter) acts as a mediator that allows the quantum signal to pass through while blocking the harmful noise components generated by the optical amplifier, thus resolving the contradiction between transmission distance and signal quality.
2Illumination intensity
If optical amplifiers are used to amplify optical signals in WDM channels, then signal strength is improved, but ASE noise and other noise components are generated
Solution Approach 1:
The patent converts the harmful noise components (ASE noise, Raman scattering, four-wave mixing) generated by the optical amplifier into identifiable spectral features that can be filtered out. By using optical filters with specific wavelength characteristics, the system exploits the spectral differences between the desired signal and the harmful noise to eliminate the noise while maintaining the amplified signal strength.
Solution Approach 2:
The patent extracts and removes the harmful noise components (ASE noise, Raman scattering, four-wave mixing) from the optical signal through optical filtering techniques. By separating the quantum signal from the amplified optical signal and removing the noise components, the system maintains the benefits of long-distance transmission while eliminating the harmful interference effects that would otherwise degrade quantum key distribution performance.
3Productivity
If quantum signals are transmitted through channels with significant signal intensity disparity between quantum and amplified optical signals, then transmission capability is improved, but quantum bit error rate increases
Solution Approach 1:
The patent introduces an intermediary filtering system between the optical amplifier and the quantum signal detection. This intermediary component (optical filter) acts as a mediator that allows the quantum signal to pass through while blocking the harmful noise components generated by the optical amplifier, thus resolving the contradiction between transmission distance and signal quality.
Solution Approach 2:
The patent extracts and removes the harmful noise components (ASE noise, Raman scattering, four-wave mixing) from the optical signal through optical filtering techniques. By separating the quantum signal from the amplified optical signal and removing the noise components, the system maintains the benefits of long-distance transmission while eliminating the harmful interference effects that would otherwise degrade quantum key distribution performance.
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 filter reduces quantum bit error rates and extends transmission distance by effectively isolating quantum signals from noise, enhancing communication reliability.
Implementation Method 1
a first fiber Bragg grating connected to the second port and configured to: reflect a wavelength component of a signal input through the first and second ports and including both a quantum signal and noise wherein the wavelength component corresponds to the quantum signal
Implementation Method 2
a first angle-cleaved fiber having a first end and a second end, the first end being connected to the first fiber Bragg grating and the second end being angle-cut to form a predetermined first angle
Data Source
AI summary
There is provided a separation filter. The separation filter includes: an optical circulator including first to fourth ports; a first fiber Bragg grating connected to the second port, reflecting a wavelength component of a signal input through the first and second ports corresponding to a quantum signal to output toward the second port; a first angle-cleaved fiber having a first end and connected to the first fiber Bragg grating and a second end angle-cut; a second fiber Bragg grating connected to the third port and reflecting a wavelength component of a signal input through the second and third ports corresponding to the quantum signal to output toward the third port; and a second angle-cleaved fiber having a first end connected to the second fiber Bragg grating and a second end angle-cut, wherein the quantum signal input through the third port is output through the fourth port.