Integrated Wavemeter Control for Broadband Light Source Stability

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Solution Overview

Problem

Existing broadband semiconductor light sources face challenges in maintaining wavelength stability over a wide range of temperatures and long operational hours due to factors like temperature gradients, optical back-reflections, and device degradation, which affects their performance in applications such as Fiber Optic Gyroscopes and optical coherence tomography.

Innovation Solution

An integrated light source module with an optical edge filter that splits the output beam into short-wavelength and long-wavelength components, detected by photodetectors, allowing for active stabilization of the mean wavelength through a feedback control system, thereby enhancing wavelength stability and reducing the need for external wavelength sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an external wavelength sensor is used to monitor and stabilize the mean wavelength, then wavelength stability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvewavelength stabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the wavelength monitoring function with the light source module itself by integrating an optical edge filter and photodetectors directly into the module. This eliminates the need for separate external wavelength sensors and creates a self-contained system that monitors and stabilizes its own output wavelength, thereby improving wavelength stability without increasing overall system complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The light source module performs self-diagnosis and self-stabilization of its wavelength output through the integrated optical edge filter and photodetector system. The module monitors its own spectral output and uses feedback control to maintain stable mean wavelength, eliminating dependency on external monitoring equipment and reducing system complexity

Inventive Principle:
Principle #25Self-service

2Device complexity

If multiple components are integrated into a single module, then device complexity is reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvesystem complexityVSAvoidintegration precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent segments the wavelength stabilization function into distinct functional components (optical edge filter, photodetectors, feedback control circuitry) that are integrated into the light source module. This modular segmentation allows for standardized manufacturing of individual components while maintaining overall system simplicity, balancing integration precision requirements with manufacturing feasibility

Inventive Principle:
Principle #1Segmentation

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 integrated wavemeter provides superior wavelength stability and sensitivity, reducing costs and complexity by eliminating the need for external wavelength sensors and improving the accuracy of wavelength readings, while allowing for customization to specific mean wavelengths and spectral shapes.

Implementation Method 1

an optical edge filter with a cross-over wavelength lying within the bandwidth of the broadband semiconductor light source, the optical edge filter being arranged to receive a portion of the output beam and divide it by transmission and reflection into short-wavelength and long-wavelength components

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

first and second photodetectors each arranged to receive one of the wavelength components reflected and transmitted by the optical edge filter and configured to output respective first and second photodetector signals indicative of the power of the wavelength component received

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP4345923A1Wavelength-stabilized broadband light source
Publication Date: 2024.04.03 INDIE TECHNOLOGIES SWITZERLAND AG
  • EP4345923A1 patent drawingFigure 1~2
  • EP4345923A1 patent drawingFigure 3~4
  • EP4345923A1 patent drawingFigure 5~6

AI summary

A light source module (100) with integrated wavemeter components (460, 494, 495) for stabilizing the output power and wavelength of a superluminescent diode or other broadband semiconductor light source (121) outputting a broadband output beam. A portion of the source output beam is directed to an optical edge filter (460) with a cross-over wavelength lying within the bandwidth of the output beam. The edge filter (460) divides the light it receives into a short-wavelength component and a long-wavelength component. These two components are then directed onto respective photodetectors (494, 495) that output respective signals to a wavemeter controller. The controller adjusts the drive current and/or temperature of the source to maintain the mean wavelength of the source's output beam at a set constant value according to a control parameter determined from a combination of the photodetector signals such as their ratio or the ratio between their difference and sum.