Tunable Local Oscillator for Coherent Optical Networks

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Solution Overview

Problem

Conventional passive optical networks (PONs) face latency and reduced throughput due to the need for electronic processing of upstream data and interference from multiple wavelengths, which degrades signal quality and increases noise in optical network units (ONUs) and optical line terminals (OLTs).

Innovation Solution

A method and optical network component utilizing a tunable element, such as a dielectric filter or angle-tunable laser, to adjust and align the local oscillator signal with the incoming optical signal, thereby suppressing interference from other wavelengths and enhancing signal-to-noise ratio and receiver sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multiple wavelengths are routed to each ONU in UDWDM network, then network capacity is increased, but interference from other wavelengths increases and degrades signal quality

Engineering Contradiction:
Improvenetwork capacityVSAvoidinterference from other wavelengths
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes unwanted wavelength components from the optical signal using a tunable filter. The filter selectively passes only the desired wavelength while blocking other wavelengths, thereby eliminating interference from unwanted channels while maintaining the ability to receive multiple wavelengths simultaneously in a UDWDM network.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies local quality by making the filter characteristics wavelength-specific. Each ONU can tune its local oscillator and filter to match the specific wavelength assigned to it, creating a localized wavelength-selective reception that allows multiple wavelengths to coexist without mutual interference.

Inventive Principle:
Principle #3Local quality

2Reliability

If local oscillator power is increased to suppress other wavelengths, then signal-to-noise ratio is improved, but power consumption and potential damage increase

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidlocal oscillator power
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

Instead of increasing LO power to suppress other wavelengths, the patent extracts and removes unwanted wavelength components using a tunable filter. This allows the use of lower LO power while achieving the same interference suppression effect, thereby improving power efficiency and reducing potential damage risks.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If electronic processing is used for upstream data, then data routing is enabled, but latency increases and throughput is degraded

Engineering Contradiction:
Improvedata routing capabilityVSAvoidnetwork latency
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent replaces electronic processing with optical wavelength-division multiplexing and filtering. By assigning different wavelengths to different data streams and using optical filters for routing, the system eliminates electronic buffering and scheduling operations, thereby reducing latency while maintaining routing capability.

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

4Stability of the object's composition

If conventional WDM with fixed channels is used, then system stability is maintained, but adaptability to different wavelength configurations is limited

Engineering Contradiction:
Improvesystem stabilityVSAvoidwavelength configuration flexibility
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamics by making the filter wavelength selectable and tunable. The filter can be dynamically adjusted to different wavelengths based on the assigned channel, allowing the system to adapt to different wavelength configurations while maintaining stable operation through controlled tuning rather than fixed hardwired connections.

Inventive Principle:
Principle #15Dynamics

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 efficiently processes optical signals by suppressing unwanted wavelength contributions, improving signal quality and reducing crosstalk, leading to increased sensitivity and throughput in optical networks.

Implementation Method 1

a first signal and a second signal are influenced by a tunable element; wherein the first signal is an incoming optical signal; wherein the second signal is a local oscillator signal generated by a laser

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

said laser comprises an optical gain element that is tuned by the tunable element

Methodology Applied
Scientific EffectOptical amplification: Laser

Data Source

PatentEP2351265B1Coherent optical system comprising a tunable local oscillator
Publication Date: 2013.02.27 XIEON NETWORKS SARL
  • EP2351265B1 patent drawingFigure 1
  • EP2351265B1 patent drawingFigure 2

AI summary

A method and an optical network component for data processing in an optical network are provided, wherein a first signal and a second signal are influenced by a tunable element, wherein the first signal is an incoming optical signal, wherein the second signal is a local oscillator signal generated by a laser and wherein said laser comprises an optical gain element that is tuned by the tunable element. Furthermore, a communication system is suggested comprising said optical network component, which can be associated with an ONU and/or with an OLT. Suitable for coherent Ultra-Dense Wavelength Division Multiplex (UDWDM) networks.