OCDM Optical Security via Spectral Phase Scrambling
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Solution Overview
Problem
Wavelength division multiplexing (WDM) networks face susceptibility to eavesdropping through inter-window cross talk and conventional means, such as physical tapping, due to shared fiber infrastructure, which compromises multi-level security.
Innovation Solution
An optical code-division multiplexing (OCDM) system using passive spectral phase encoding (SPE) with shared spectral phase scrambling and descrambling, along with orthogonal codes and micro-ring resonator filters, provides enhanced security by encrypting data signals and making them unintelligible without the proper decryption key, even if inadvertently leaked.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wavelength division multiplexing is used to carry different security levels on the same fiber, then network capacity and resource utilization are improved, but security is worsened due to susceptibility to eavesdropping through inter-window cross talk and physical tapping
Solution Approach 1:
The patent introduces OCDM codes as an intermediary layer between the WDM channels and the security requirement. Each security level is encoded with a unique orthogonal code, creating an intermediate representation that requires code correlation for decryption. This intermediary encoding layer prevents direct eavesdropping on WDM channels while maintaining high network capacity through wavelength multiplexing
Solution Approach 2:
The patent transforms the security parameter from physical layer isolation (separate fibers) to signal layer encoding (orthogonal codes). By changing the security mechanism from spatial separation to spectral-phase encoding, the system achieves both high capacity through WDM and security through code-based encryption, resolving the contradiction between network productivity and security reliability
2Reliability
If separate fibers are used for different security levels, then security is improved by preventing cross talk eavesdropping, but network cost and infrastructure complexity are worsened
Solution Approach 1:
The patent merges multiple security levels into a single fiber infrastructure by using OCDM encoding. Instead of requiring separate physical fibers for each security level, the system combines multiple encoded channels in the same fiber using orthogonal codes, thereby reducing infrastructure complexity while maintaining security through code-based separation
Solution Approach 2:
The patent makes the single fiber infrastructure universal by enabling it to carry multiple security levels simultaneously through OCDM encoding. The same physical medium performs multiple security functions through spectral-phase coding, eliminating the need for dedicated fibers for each security level and reducing overall system complexity
3Productivity
If WDM channels are multiplexed on the same fiber, then network efficiency is improved, but susceptibility to eavesdropping through cross talk is worsened
Solution Approach 1:
The patent introduces orthogonal OCDM codes as an intermediary encoding layer that protects WDM channels from cross talk eavesdropping. Each channel is spectrally-phase encoded with a unique orthogonal code, creating an intermediate representation that requires code correlation for successful decryption, thereby neutralizing the harmful effect of cross talk while maintaining network efficiency
Solution Approach 2:
The patent converts the harmful cross talk effect into a beneficial security feature. The presence of multiple WDM channels creates cross talk, but the patent uses orthogonal coding to ensure that cross talk appears as random noise to unauthorized receivers. The harmful physical phenomenon of cross talk is thus transformed into an effective encryption mechanism that maintains network efficiency while preventing eavesdropping
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 OCDM system ensures robust security against eavesdropping by phase scrambling and frequency shuffling, making it impractical for eavesdroppers to decipher signals, even with exhaustive searches, and reduces multi-channel interference through optical time gating, thus maintaining data integrity and security within WDM networks.
Implementation Method 1
Each filter is a fourth-order micro-ring resonator filter
Implementation Method 2
each filter is a fourth-order micro-ring resonator filter
Implementation Method 3
a shared spectral phase scrambler for phase scrambling the composite transport data signal using a shared scramble code as an encryption key
Implementation Method 4
In wavelength division multiplexing networks, different security levels are carried on the same fiber, but on different optical channels
Implementation Method 5
An optical code-division multiplexing (OCDM) system using passive spectral phase encoding (SPE) with shared spectral phase scrambling and descrambling
Data Source
AI summary
A high data rate optical signal is inverse multiplexed into a multitude of lower-rate tributaries, each of which is coded by its unique OCDM code, and the combined coded tributaries are injected into a common phase scrambler. Coherent summation of these optically encoded tributaries pass through a shared phase or phase and frequency scrambler before exiting the secure location. The setting of the scrambler acts as the key. The authorized recipient with the correct key retrieves the ones and zeros of the several decoded signals.