Dispersion Compensating Optical Fiber Link for Quantum Key Bit Rate
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Solution Overview
Problem
Current quantum communication systems face limitations in achieving high quantum key bit rates due to dispersion and attenuation issues in optical fiber links, which hinder the efficient transmission of quantum key information.
Innovation Solution
The implementation of a quantum communications system that includes a photonic quantum bit generator, a dispersion compensating optical fiber link, and a photon detector unit, where the optical fiber link is structured to induce minimal dispersion and attenuation, enabling the transmission of quantum key bit information at rates of at least 10 Gbit/sec by optimizing the core and cladding configuration to manage photon pulses effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional optical fiber links are used for quantum key transmission, then the system structure is simple, but dispersion and attenuation limit the quantum key bit rate to below 10 Gbit/sec
Solution Approach 1:
The patent changes the physical parameters of the optical fiber by introducing a specific refractive index profile with multiple cladding layers (first cladding with refractive index n1, second cladding with refractive index n2 where n1 > n2). This parameter change in the fiber structure enables dispersion compensation, allowing high-speed quantum key transmission at 10 Gbit/sec while maintaining signal quality through controlled chromatic dispersion characteristics.
2Reliability
If dispersion compensation is implemented using traditional methods, then signal quality improves, but system complexity and device configuration become more complicated
Solution Approach 1:
The patent merges the dispersion compensation function directly into the optical fiber structure itself by designing a multi-layer cladding configuration. Instead of using separate dispersion compensation modules or devices, the fiber's own structural design (with its specific refractive index profiling) provides the dispersion compensation, thereby improving signal quality while avoiding additional device complexity.
3Productivity
If high bit rate transmission is achieved, then productivity increases, but signal loss and attenuation increase
Solution Approach 1:
The patent optimizes the refractive index parameters of the cladding layers to achieve a balance between dispersion compensation and attenuation reduction. The specific configuration where the first cladding has refractive index n1 and the second cladding has refractive index n2 (with n1 > n2) creates favorable propagation characteristics that reduce photon attenuation while enabling high-speed transmission at 10 Gbit/sec.
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 ensures reliable and high-speed transmission of quantum key information, enhancing the bit rate and reducing signal loss, thereby improving the efficiency of quantum key generation and communication systems.
Implementation Method 1
the dispersion compensating optical fiber link... is structurally configured to induce dispersion of a photon comprising a wavelength of about 1550 nm at an absolute dispersion rate of about 9 ps/(nm)km or less
Implementation Method 2
induce attenuation of the photon comprising the wavelength of about 1550 nm at an attenuation rate of about 0.18 dB/Km or less
Data Source
AI summary
A quantum communications system includes a quantum key generation system having a photonic quantum bit generator, a dispersion compensating optical fiber link, and a photon detector unit and a communications network having a signal generator, a signal channel, and a signal receiver. The dispersion compensating optical fiber link extends between and optically couples the photonic quantum bit generator and the photon detector unit. Further, the dispersion compensating optical fiber link is structurally configured to induce dispersion at an absolute dispersion rate of about 9 ps/(nm)km or less and induce attenuation at an attenuation rate of about 0.18 dB/Km or less such that the quantum key bit information of a plurality of photons output by the one or more photonic quantum bit generators is receivable at the photon detector unit at a bit rate of at least about 10 Gbit/sec.