Tunable Laser Reflectivity Control for Linewidth Stability

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Solution Overview

Problem

Tunable semiconductor lasers experience performance deterioration due to changes in service time or operating environment, as the relationship between the driving condition and reflectivity of the reflector becomes altered, leading to increased noise, linewidth, and decreased side mode suppression ratio.

Innovation Solution

Incorporating a first and second detector to convert optical signals from the reflectors into electrical signals, which are then used by a controller to adjust the reflectivity of the reflectors, ensuring alignment with the target wavelength and maintaining optimal performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the driving condition of the reflector is fixedly set based on a target wavelength, then the tunable laser can operate at the target wavelength, but the performance deteriorates as service time or operating environment changes

Engineering Contradiction:
Improveperformance stabilityVSAvoidadaptability to environment changes
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a feedback mechanism where detectors monitor the optical signals from the reflectors and convert them to electrical signals. The controller uses these electrical signals to dynamically adjust the driving conditions of the reflectors, forming a closed-loop control system that maintains optimal performance despite environmental changes or aging effects.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transitions from a static fixed driving condition to a dynamic adjustable driving condition. The controller continuously adjusts the driving conditions of the reflectors based on real-time feedback from the detectors, enabling the system to adapt to changing service conditions and operating environments while maintaining performance stability.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If the reflectivity of the reflector is adjusted to maintain wavelength alignment, then the side mode suppression ratio improves, but the system complexity increases due to additional detectors and controllers

Engineering Contradiction:
Improvewavelength alignment precisionVSAvoidsystem structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a self-service mechanism where the system automatically monitors and adjusts its own operating parameters. The detectors monitor the optical signals and the controller automatically adjusts the reflector driving conditions based on the detected signals, eliminating the need for external manual calibration or intervention while maintaining precise wavelength alignment.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The feedback loop formed by the detectors and controller enables automatic wavelength alignment. The detectors provide real-time information about the optical signals, and the controller uses this information to adjust the reflector driving conditions, creating a self-correcting system that maintains precise wavelength alignment without increasing operational complexity.

Inventive Principle:
Principle #23Feedback

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 solution prevents performance deterioration by dynamically adjusting the reflectivity of the reflectors, maintaining high linewidth and side mode suppression ratio, even under varying conditions, thus ensuring the authenticity of technical specifications.

Implementation Method 1

a first detector configured to convert an optical signal of the first reflector into a first electrical signal

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Implementation Method 2

a second detector configured to convert an optical signal of the second reflector into a second electrical signal

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentEP3392986B1Tunable laser and controlling method therefor
Publication Date: 2020.05.13 HUAWEI TECH CO LTD
  • EP3392986B1 patent drawingFigure 1~2.2
  • EP3392986B1 patent drawingFigure 2.3~3.1
  • EP3392986B1 patent drawingFigure 3.2~4.1

AI summary

A tunable laser is provided, including a first reflector (11), a second reflector (12), a phase adjustment area (13), a gain area (14), a first detector (15), a second detector (16), and a controller (50). The phase adjustment area (13) is located between the first reflector (11) and the gain area (14), the gain area (14) is located between the phase adjustment area (13) and the second reflector (12), a reflectivity of the first reflector (11) is adjustable, and a reflectivity of the second reflector (12) is adjustable. The first detector (15) is configured to convert an optical signal of the first reflector (11) into a first electrical signal. The second detector (16) is configured to convert an optical signal of the second reflector (12) into a second electrical signal. The controller (50) is configured to adjust at least one of the reflectivity of the first reflector (11) or the reflectivity of the second reflector (12) based on the first electrical signal and the second electrical signal. The reflectivity of the reflectors (11 and 12) can be adjusted, so that performance deterioration of the tunable laser can be prevented.