Optical Control Channel via Digital Amplitude Modulation

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Solution Overview

Problem

Existing methods for creating and extracting control channels in optical transmission signals in optical networks, such as WDM-PON, require additional hardware components like DACs, ADCs, or DDS, increasing costs and complexity.

Innovation Solution

Implementing a digital modulation scheme to amplitude-modulate the optical carrier signal, using a binary digital modulation scheme to create a control channel without the need for additional hardware, allowing the control information to be used for wavelength tuning of optical transmitters or receivers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If analog amplitude modulation is used to create control channel with pilot tone, then control information can be transported in optical transmission signal, but additional hardware components (DAC, ADC, DDS) are required increasing device complexity and cost

Engineering Contradiction:

Improvecontrol channel functionalityVSAvoidhardware components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical/electronic analog modulation system (requiring DAC, ADC, DDS components) with a digital signal processing approach. The control channel is created by digitally modulating the optical carrier signal using standard digital modulation techniques, eliminating the need for separate analog modulation hardware while maintaining control information transport capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent makes the existing digital modulation components in the optical transmitter perform dual functions: transmitting user data information and simultaneously creating the control channel with pilot tone. The same digital signal processor that modulates user data also generates the control channel signal, eliminating dedicated control channel hardware

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If additional components are added to create control channel, then control information transport is enabled, but manufacturing cost increases

Engineering Contradiction:

Improvecontrol information transportVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent enables existing digital modulation components to perform multiple functions - both user data transmission and control channel creation - eliminating the need for additional dedicated hardware components and reducing manufacturing costs

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the control channel creation function with the existing digital modulation subsystem. The pilot tone and control information are integrated into the same digital signal processing chain that handles user data, combining multiple functions into a single hardware platform

Inventive Principle:

Principle #5Merging (Combining)

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 eliminates the need for extra components in transmitters and receivers, reducing costs and complexity while maintaining effective control channel functionality, allowing precise wavelength control in optical networks.

Implementation Method 1

amplitude-modulating (the power or, more specifically, the average optical power of) an optical carrier signal or a modulated optical carrier signal using a digital modulation scheme only

Methodology Applied

Scientific EffectAmplitude modulation: Phase Modulation

Data Source

PatentEP3079284B1Method and device for creating a control channel in an optical transmission signal and method and device for extracting the information included therein

Publication Date: 2019.04.03 ADVA OPTICAL NETWORKING SP ZOO

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AI summary

The invention relates to a method for creating a control channel in an optical transmission signal, wherein the optical transmission signal (SDS,i; SUS,i) comprises an optical carrier frequency component, a higher frequency modulation component carrying user information to be transported from a first end to a second end of an optical transmission link and a lower frequency modulation component carrying control information, the higher frequency modulation component realizing a user channel and the lower frequency modulation component realizing the control channel, and wherein the lower frequency modulation component is created by amplitude modulation. According to the invention, the lower frequency modulation component comprises a binary digital pilot tone signal component which corresponds to a pilot tone signal having a predetermined pilot tone frequency (fi).