Optical Transmission via Nonlinear Spectral Shift

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Solution Overview

Problem

Current passive optical networks (PONs) face challenges in cost, complexity, and security due to the need for multiple wavelengths and demultiplexers, especially in conventional PONs, and high-speed communication requirements.

Innovation Solution

A method of optical transmission using a single wavelength signal that is amplitude multiplexed and transformed into multiple wavelengths through nonlinear spectral shift, allowing each unit to receive specific wavelengths, simplifying the network architecture and enhancing security and performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional PONs use time-division multiple access with a single wavelength, then device complexity is reduced, but signal attenuation increases and security concerns arise

Engineering Contradiction:
Improvetransmitter complexityVSAvoidsignal attenuation
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent segments the single wavelength signal into multiple wavelength components using amplitude multiplexing and nonlinear spectral shift. Each client terminal receives a specific wavelength component, effectively dividing the transmission resource while maintaining low device complexity at the transmitter.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the wavelength parameter dynamically through nonlinear spectral shift. A single wavelength signal is transformed into multiple wavelengths based on amplitude variations, allowing each client to receive a distinct wavelength without requiring multiple transmitters.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If WDM PONs allocate a specific wavelength to each subscriber, then signal attenuation is reduced and performance improves, but device complexity and cost increase due to multiple demultiplexers

Engineering Contradiction:
Improvesignal attenuationVSAvoiddemultiplexer quantity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent makes a single demultiplexer universal by enabling it to handle multiple wavelength components that are dynamically assigned. Instead of requiring one demultiplexer per client, a single demultiplexer serves all clients by processing the wavelength-multiplexed signal generated through nonlinear spectral shift.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the functions of multiple demultiplexers into a single demultiplexer. By combining multiple wavelength components into one signal stream using amplitude multiplexing and nonlinear spectral shift, the system eliminates the need for separate demultiplexers at each client terminal.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If a tunable laser switches between multiple wavelengths to address different customers, then wavelength allocation flexibility improves, but transmission speed decreases due to switching time

Engineering Contradiction:
Improvewavelength allocation flexibilityVSAvoidtransmission speed
Core Design Contradiction:
Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent uses periodic amplitude modulation of a single wavelength signal to encode multiple wavelength components. This periodic action in the time domain is transformed into wavelength domain separation through nonlinear spectral shift, eliminating the need for mechanical or electronic switching while maintaining wavelength allocation flexibility.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent replaces the mechanical or electronic switching mechanism of tunable lasers with a nonlinear optical process. Instead of physically switching wavelengths, the system uses amplitude multiplexing followed by nonlinear spectral shift to generate multiple wavelengths simultaneously, thereby eliminating switching time delays.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach reduces costs, increases security, and simplifies the network by allowing each unit to receive specific wavelengths, improving the overall efficiency and reliability of the PON.

Implementation Method 1

the single wavelength of the light signal sent by the first unit is transformed by a nonlinear spectral shift effect into a plurality of wavelengths according to the plurality of amplitudes

Methodology Applied
Scientific EffectNonlinear spectral shift:

Data Source

PatentEP1867086B1Optical transmission between a first unit and a plurality of second units interconnected by means of a passive optical access network
Publication Date: 2008.08.20 ORANGE SA
  • EP1867086B1 patent drawingFigure 1~2
  • EP1867086B1 patent drawingFigure 3~4
  • EP1867086B1 patent drawingFigure 5~6

AI summary

The invention concerns an optical transmission system and method providing for transmission of a downlink and uplink data traffic between a central terminal (15) and a plurality of client terminals (17) being interconnected by means of a passive optical access network (5), including the following steps: transmitting data borne by an amplitude-multiplexed light signal (S) comprising a plurality of amplitudes and having a single wavelength to the plurality of client terminals (17); transforming by spectral shifting, the single wavelength of said light signal (S) sent by said central terminal (15) into a plurality of wavelengths, based on the plurality of amplitudes thus forming a wavelength division multiplexed light signal, so that said data are received by said plurality of client terminals (17) based a plurality of light signals (S1,, SN) having a plurality of different wavelengths, each of said client terminals (17) receiving the data which are associated therewith based at least on one specific wavelength; and routing said downlink and uplink traffic between said central terminal (15) and the client terminals (17).