Slope Gain Equalizer With Dual-Core Bidirectional Filtering

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Solution Overview

Problem

The construction of optical fiber communication systems is hindered by the need for various slope gain equalizers with different correction characteristics, leading to increased costs due to stock management and prolonged construction times.

Innovation Solution

A slope gain equalizer using a dual-core fiber collimator and interference filter with a dielectric multilayer film, capable of correcting slope gain characteristics regardless of slope direction, reducing the need for multiple equalizers and simplifying system construction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a wide variety of slope gain equalizers with different correction characteristics are prepared in advance, then the construction time of optical fiber communication systems is shortened, but stock management costs and manufacturing costs increase

Engineering Contradiction:
Improveconstruction timeVSAvoidstock management costs
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent applies universality by designing a single slope gain equalizer that can correct multiple types of slope gain characteristics (positive slope, negative slope, and zero slope) through a unified structure. The dielectric multilayer film is configured with specific refractive indices and thickness ratios that enable it to function as a universal corrector for various slope directions and magnitudes, eliminating the need to maintain multiple specialized equalizers in stock.

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

2Quantity of substance

If the specification of the slope gain equalizer is decided after the slope gain characteristic is determined, then stock management costs are reduced, but the construction time of optical fiber communication systems is prolonged

Engineering Contradiction:
Improvestock management costsVSAvoidconstruction time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-configuring the dielectric multilayer film with specific optical characteristics (refractive indices and thickness ratios) that provide universal correction capability. This preliminary design allows the equalizer to be manufactured as a standardized component that can adapt to various slope gain characteristics without requiring post-manufacturing customization, thus reducing both stock management costs and construction time.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If multiple slope gain equalizers are maintained in stock, then system construction can proceed quickly, but manufacturing costs of unused equalizers increase overall system cost

Engineering Contradiction:
Improvesystem construction speedVSAvoidoverall system cost
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent reduces overall system cost by creating a universal slope gain equalizer that can handle various slope gain characteristics with a single design. This eliminates the need to manufacture and stock multiple specialized equalizers, thereby reducing both the manufacturing costs of unused components and the overall system cost while maintaining fast construction speed.

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

Reduces stock management costs and accelerates the construction of optical fiber communication systems by allowing a single equalizer to correct slope gain characteristics in both directions, thereby lowering overall system costs.

Implementation Method 1

a gain equalizer using a dielectric multilayer is described in the following NPL 3

Methodology Applied
Scientific EffectOptical interference: Interference

Data Source

PatentEP4054092B1Slope gain equalizer
Publication Date: 2025.09.17 KOHOKU KOGYO CO LTD
  • EP4054092B1 patent drawingFigure 1~2
  • EP4054092B1 patent drawingFigure 3A~3B
  • EP4054092B1 patent drawingFigure 4

AI summary

A slope gain equalizer 1 that corrects a slope of a gain characteristic of an optical signal in a predetermined wavelength bandwidth, in which an interference filter 5, which allows insertion losses in a predetermined wavelength region to be inclined in opposite directions between a transmitting direction and a reflecting direction from a short wavelength side to a long wavelength side, is arranged between a dual-core fiber collimator 3 and a single-core fiber collimator 4 arranged to face each other on an optical axis 100, an optical signal of a predetermined bandwidth that is inputted from a first or a second optical fiber (7 or 8) held by the dual-core fiber collimator is reflected by the interference filter and outputted from the second or the first optical fiber, and an optical signal inputted from a third optical fiber 11 held by the first optical fiber or the single-core fiber collimator is transmitted through the interference filter and outputted from the third or the first optical fiber.