Optical Wavelength Multiplexer With Segmented Waveguide Groups

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Solution Overview

Problem

Conventional optical wavelength multiplexers/demultiplexers, particularly arrayed waveguide gratings (AWGs), face limitations in increasing the interval between adjacent waveguides beyond the channel frequency interval, which restricts bandwidth extension and reduces capacity in high-speed communication systems.

Innovation Solution

The optical wavelength multiplexer/demultiplexer design features a fan-shaped arrayed waveguide with varying lengths and a configuration where the first I/O waveguide branches into two inputs connected to parabolic waveguides displaced at predetermined intervals, allowing the second I/O waveguide to have waveguide groups with a double channel frequency interval, enabling a wider waveguide separation and increased bandwidth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the channel frequency interval is increased to extend the band property for high-speed modulation, then the bandwidth is improved, but the total number of channels within the operating wavelength range decreases, leading to reduced total capacity

Engineering Contradiction:
ImprovebandwidthVSAvoidtotal number of channels
Core Design Contradiction:
SpeedVSQuantity of substance

Solution Approach 1:

The invention divides the output waveguides into multiple groups (first output waveguide group and second output waveguide group) with different pitch intervals. The first group has pitch P1 and the second group has pitch P2, where P2 > P1. This segmentation allows different output waveguides to serve different channel intervals, enabling the system to maintain both wide bandwidth (using larger pitch P2) and high channel density (using smaller pitch P1) simultaneously, thus resolving the contradiction between bandwidth extension and total channel capacity.

Inventive Principle:
Principle #1Segmentation

2Speed

If the width of I/O waveguides is increased to improve transmission properties, then the bandwidth is improved, but the waveguide width is limited by the channel frequency interval between adjacent waveguides

Engineering Contradiction:
ImprovebandwidthVSAvoidwaveguide width flexibility
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

The invention applies different pitch intervals to different output waveguide groups. The first output waveguide group uses a smaller pitch P1 suitable for certain channel intervals, while the second output waveguide group uses a larger pitch P2 suitable for other channel intervals. This local differentiation of pitch intervals allows each waveguide group to be optimized for its specific function, enabling wider waveguide widths and better transmission properties without being constrained by a uniform channel frequency interval across all waveguides.

Inventive Principle:
Principle #3Local quality

3Speed

If the interval between adjacent waveguides is increased beyond the channel frequency interval, then the bandwidth is extended, but the mechanical interval definition by channel frequency interval restricts this increase in conventional AWG

Engineering Contradiction:
ImprovebandwidthVSAvoidwaveguide interval configuration
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The invention segments the output waveguides into multiple groups with different pitch intervals. By having the first output waveguide group with pitch P1 and the second output waveguide group with pitch P2 (where P2 > P1), the system can accommodate waveguide intervals larger than the channel frequency interval in the second group, thereby extending bandwidth while maintaining manageable device complexity through organized grouping.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces an additional dimension of differentiation by creating multiple output waveguide groups with different pitch characteristics. Instead of using a single uniform pitch for all output waveguides, the system varies the pitch across different groups, adding a dimensional aspect to the waveguide configuration that enables broader bandwidth while keeping the overall device structure organized and manageable.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 design effectively doubles the waveguide interval, enhancing bandwidth and maintaining uniform transmission properties across channels, facilitating miniaturization and cost reduction while supporting high-speed, high-capacity communication.

Implementation Method 1

an arrayed waveguide grating (AWG) including waveguides formed on a planar substrate

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

a parabolic waveguide 106 provided between the one I/O waveguide 101 and the one slab waveguide 102

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3705917B1Optical wavelength multiplexer/demultiplexer
Publication Date: 2021.09.08 NTT ELECTORNICS CORP
  • EP3705917B1 patent drawingFigure 1
  • EP3705917B1 patent drawingFigure 2
  • EP3705917B1 patent drawingFigure 3

AI summary

A broadband optical wavelength multiplexer/demultiplexer is provided that can satisfy a transmission band required for a high-speed modulation scheme without an increase in channel interval. Two waveguides are arranged such that, in a case where a connection position where one of the two waveguides is connected to a first slab waveguide is set closer to the other waveguide by a channel frequency interval Δf, a central position between the two waveguides aligns with a central position on a connection end surface of the first slab waveguide, and two waveguide groups of an output waveguide are arranged such that a central position between the two waveguide groups aligns with a central position of a second slab waveguide, and an interval between a connection position where the other waveguide is connected to the first slab waveguide and the central position on the connection end surface of the first slab waveguide is set equal to an interval between a connection position where the waveguide groups are connected to the second slab waveguide and a central position on a connection end surface of the second slab waveguide, and an interval between adjacent waveguides in each of the two waveguide groups is set double the channel frequency interval.