Tunable Optical Add/Drop Multiplexer With Grating-Assisted Filters

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Solution Overview

Problem

Current optical add/drop multiplexers lack tunability, which restricts bandwidth and fails to meet the flexibility requirements of evolving communication services, necessitating a solution to adapt to dynamic network demands.

Innovation Solution

A tunable optical add/drop multiplexer (T-OADM) system utilizing two grating-assisted filters (GAFs) connected in series, with wavelength control units to adjust spectral bandwidth and center wavelength, enabling flexible bandwidth tuning and improved system adaptability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional optical add/drop multiplexer methods are used, then the device can be manufactured with existing CMOS process lines and low-cost silicon materials, but the bandwidth is untunable and system flexibility is insufficient

Engineering Contradiction:
Improvebandwidth tunabilityVSAvoiddevice structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the optical filter bandwidth tunable through thermal control. The filter's spectral characteristics can be dynamically adjusted by changing the temperature of the silicon-based waveguide, allowing the bandwidth to adapt to different service requirements rather than being fixed during manufacturing.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes physical parameters by utilizing thermal effects to modify the refractive index of the silicon waveguide. By controlling the temperature parameter, the optical filter's bandwidth and center wavelength can be adjusted, enabling flexible bandwidth tuning while maintaining the same physical device structure.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If new communication services with higher dynamic characteristics are supported, then system flexibility requirements increase, but conventional optical add/drop multiplexers cannot satisfy these requirements due to fixed bandwidth

Engineering Contradiction:
Improvesystem flexibilityVSAvoidservice compatibility
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements dynamics by enabling real-time adjustment of the optical filter bandwidth through thermal control mechanisms. This allows the system to adapt its bandwidth characteristics to match the dynamic requirements of different communication services, ensuring both flexibility and reliable service compatibility.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent achieves universality by designing a single optical filter structure that can serve multiple service types with different bandwidth requirements. Through thermal tuning, the same device can accommodate various service scenarios, from narrowband to wideband applications, eliminating the need for multiple specialized devices.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If two grating-assisted filters are used in series to achieve bandwidth tuning, then channel bandwidth can be adjusted to improve system flexibility, but the device complexity increases

Engineering Contradiction:
Improvebandwidth adjustabilityVSAvoidfilter structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the bandwidth tuning function into two separate grating-assisted filters connected in series. Each filter can be independently controlled through thermal mechanisms, allowing granular adjustment of the overall bandwidth while maintaining manageable complexity for each individual filter component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges two grating-assisted filters in series to achieve enhanced bandwidth tuning capabilities. By combining the filtering functions of two devices, the system can selectively adjust bandwidth across different spectral regions, improving overall adaptability while distributing the complexity across multiple simpler components.

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

The T-OADM system enhances system flexibility by dynamically adjusting channel bandwidth and center wavelength, effectively accommodating diverse service requirements and improving network adaptability.

Implementation Method 1

two grating-assisted filters GAFs

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

A specific working process of the optical add/drop multiplexer is as follows: The second wavelength control unit changes a dropped spectrum of the second GAF based on first amplitude of wavelength shift

Methodology Applied
Scientific EffectThermo-optic effect: Temperature Gradient

Data Source

PatentEP3480980B1Optical add/drop multiplexer, control method therefor, and transceiver
Publication Date: 2021.04.07 HUAWEI TECH CO LTD
  • EP3480980B1 patent drawingFigure 1~2b
  • EP3480980B1 patent drawingFigure 3
  • EP3480980B1 patent drawingFigure 4

AI summary

Embodiments of the present invention provide an optical add/drop multiplexer, including a plurality of tunable optical add/drop multiplexers T-OADMs. Each T-OADM includes a second wavelength control unit and two grating-assisted filters GAFs. The second wavelength control unit is connected to a second GAF. A drop port of a first GAF is connected to an input port of the second GAF. An add port of the first GAF is connected to an output port of the second GAF. An input port of the first GAF receives light waves of a plurality of wavelengths. The first GAF transmits a first light wave to the input port of the second GAF through the drop port of the first GAF. The second wavelength control unit changes a dropped spectrum of the second GAF based on first amplitude of wavelength shift, to obtain a first light wave response. A drop port of the second GAF outputs a first target light wave of a first target bandwidth. The embodiments of the present invention further provide a control method for an optical add/drop multiplexer and a transceiver.