Wavelength Sweep Control for Optical Interrogation

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Solution Overview

Problem

Current optical systems face inefficiencies in measuring characteristic wavelengths due to high signal-to-noise ratio (SNR) issues and prolonged interrogation times, especially in wavelength-division multiplexing (WDM) schemes, where guard-bands increase the scanned range and reduce useful signal production.

Innovation Solution

Implementing a method and apparatus that utilize an amplified spontaneous emission (ASE) source, a tunable filter, and an amplifier to control the wavelength sweep, allowing for variable sweep rates and bandpass adjustments based on the light's wavelength, thereby optimizing the received signal and reducing unnecessary interrogation time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fixed spectral bandwidth sweep is used to interrogate optical elements, then the measurement covers the full wavelength range including guard-bands, but a large percentage of interrogation time is spent covering wavelengths where no useful signal is returned

Engineering Contradiction:

Improvecharacteristic wavelength measurement accuracyVSAvoidinterrogation time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the spectral bandwidth sweep adaptive rather than fixed. The system dynamically adjusts the sweep range based on detected signal characteristics, concentrating measurement time on wavelength regions containing useful signals from optical elements while reducing or eliminating sweeps through guard-band regions where no signals are expected.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements local quality by applying different sweep strategies to different wavelength regions. High-resolution sweeps are applied to regions containing optical element signals, while guard-band regions receive reduced or skipped sweeps, optimizing measurement quality where needed and reducing time where unnecessary.

Inventive Principle:

Principle #3Local quality

2Reliability

If guard-bands are included in the wavelength sweep to ensure non-overlapping spectral features, then measurement reliability is maintained, but the total range of wavelengths scanned increases, reducing the proportion of useful signal time

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoiduseful signal production rate

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent extracts guard-band regions from the active measurement sweep, separating them from the useful signal regions. By identifying and excluding guard-band wavelength ranges from the sweep profile, the system maintains measurement reliability through proper element spacing while eliminating wasted interrogation time in regions that cannot contain useful signals.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies skipping by rapidly traversing or entirely omitting guard-band regions during the wavelength sweep. The system identifies guard-band locations and either skips them completely or rushes through them with minimal sampling, thereby maintaining measurement reliability while maximizing the proportion of time spent acquiring useful signals.

Inventive Principle:

Principle #21Skipping (Rushing through)

3Measurement precision

If the wavelength sweep covers the entire expected measurement range with sufficient resolution, then measurement accuracy is improved, but the effective integration time is reduced due to increased total sweep time

Engineering Contradiction:

Improvecharacteristic wavelength measurement repeatabilityVSAvoideffective integration time

Core Design Contradiction:

Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The patent implements periodic action through multi-pass wavelength sweeping, where the sweep is repeated multiple times with optimized parameters. By performing several shorter, focused sweeps at optimized resolution levels rather than one comprehensive high-resolution sweep, the system accumulates effective integration time while maintaining measurement precision through repeated measurements.

Inventive Principle:

Principle #19Periodic action

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 enhances the accuracy and repeatability of characteristic wavelength measurements by increasing the percentage of useful signal time and reducing overall interrogation time, allowing for more focused measurements on regions of interest.

Implementation Method 1

filtering light emitted from an amplified spontaneous emission (ASE) source

Methodology Applied

Scientific EffectAmplified spontaneous emission:

Implementation Method 2

amplifying the filtered light

Methodology Applied

Scientific EffectOptical amplification:

Implementation Method 3

filtering the reflected optical signals, wherein a bandpass wavelength range is changed based on the sweep function

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentUS9007679B2Wavelength sweep control

Publication Date: 2015.04.14 WEATHERFORD TECHNOLOGY HOLDINGS LLC

AI summary

Methods and apparatus for the active control of a wavelength-swept light source used to interrogate optical elements having characteristic wavelengths distributed across a wavelength range are provided.