Optical Fiber Filter With 2D Mirror Switching for C+L Band Tuning

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Solution Overview

Problem

Current tunable optical fiber filters have a limited tuning range of 40 to 50 nm, requiring multiple devices to cover the C+L bands, which is costly and bulky.

Innovation Solution

An optical fiber filter with a two-dimensional mechanical rotating mirror, collimating and beam expanding system, and gratings, allowing for ultra-wide tuning by switching between C and L bands using the mirror's two-dimensional movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single tunable optical fiber filter is used with limited tuning range (40-50 nm), then the device structure remains simple and cost-effective, but it cannot cover the ultra-wide C+L band tuning range required for DWDM systems

Engineering Contradiction:

Improvewavelength tuning rangeVSAvoiddevice structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The optical filter is segmented into multiple independent filtering units, each optimized for a specific wavelength band (C-band or L-band). By selectively activating only the required band, the system achieves ultra-wide tuning range while maintaining simple structure for each active unit, avoiding the complexity of a single device covering all bands simultaneously

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The filter employs dynamic band selection capability where different filtering units can be activated or deactivated based on operational requirements. This dynamic switching between C-band and L-band modes enables the system to adapt to different wavelength ranges without requiring all components to be active simultaneously, thus maintaining structural simplicity while achieving versatility

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If two independent optical fiber filters are used to cover C and L bands separately, then the ultra-wide tuning range is achieved, but the system cost and volume increase significantly

Engineering Contradiction:

Improvewavelength tuning rangeVSAvoidnumber of devices

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

Multiple filtering units for different wavelength bands (C-band and L-band) are merged into a single integrated optical filter device. This consolidation allows the system to achieve ultra-wide tuning range across both bands while reducing the total number of discrete devices from two to one, thereby decreasing system volume and associated costs

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If two independent optical fiber filters are deployed for C and L bands, then complete band coverage is achieved, but the system cost increases due to multiple devices

Engineering Contradiction:

Improvewavelength tuning rangeVSAvoidsystem cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The optical filter is designed with multi-functional capability to handle both C-band and L-band wavelengths within a single device architecture. By incorporating multiple filtering units that can be selectively activated, the device performs multiple functions (filtering different bands) without requiring separate dedicated devices for each band, thus reducing overall system cost

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Achieves a stable, low-cost, and reliable ultra-wide tuning range in the C+L bands, reducing costs and simplifying the optical path for fast tuning and expanded channel multiplexing.

Implementation Method 1

an input optical fiber emits a multi-wavelength optical signal to a two-dimensional mechanical rotating mirror, and the optical signal is reflected to a collimating and beam expanding system

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

the optical signal is reflected to a collimating and beam expanding system to form collimated beams

Methodology Applied

Scientific EffectCollimation: Lens

Implementation Method 3

The collimated beams are incident on gratings that generate dispersion to scatter different wavelengths at different angles

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 4

gratings that generate dispersion to scatter different wavelengths at different angles

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 5

Collimated beams from the collimating and beam expanding system are reflected by the first total reflection components and enter into the respective gratings, which disperse the beams to the second total reflection components

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS12625324B2Optical fiber filter with ultra-wide tuning range

Publication Date: 2026.05.12 II VI DELAWARE INC

AI summary

An optical fiber filter has an ultra-wide tuning range and includes a two-dimensional mechanical rotating mirror, a collimating and beam expanding system, and two gratings. An input fiber emits a multi-wavelength optical signal into the rotating mirror, which reflects the signal to the system to form collimated beams. In turn, the collimated beams are incident on the gratings that disperse the light of different wavelengths to different angles. Lights of different diffraction angles are input into an output fiber by adjusting the rotating mirror. The rotating mirror can be used to switch between gratings of different wavebands to tune optical wavelengths in an ultra-wide range.