Arrayed Waveguide Phase Correction Using Tunable Reflectors

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Solution Overview

Problem

Arrayed waveguide gratings in integrated photonics suffer from phase errors due to geometrical deformations and material variations, leading to increased insertion loss and crosstalk, which are difficult to correct in a compact form.

Innovation Solution

An integrated photonics arrayed waveguide multiplexing/demultiplexing device with tunable reflectors and phase correcting regions that adjust optical path lengths to correct phase errors, using semi-transparent reflectors to generate reflected light for error evaluation and correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If phase errors in arrayed waveguide gratings are corrected using traditional methods, then performance improves, but device size increases significantly

Engineering Contradiction:
Improvephase error correctionVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent embeds tunable reflectors within the waveguide structure itself, nesting the correction mechanism inside the existing device footprint. The reflectors are positioned at specific locations along the waveguides, allowing phase correction without adding external bulk to the device.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent utilizes the vertical dimension by implementing tunable reflectors that operate in the transverse plane of the waveguide. This allows phase correction to be achieved through vertical positioning and tuning of reflector elements rather than requiring additional horizontal space.

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

2Manufacturing precision

If waveguide geometry variations are reduced to minimize phase errors, then manufacturing precision must increase, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvewaveguide geometry controlVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent implements a feedback mechanism where tunable reflectors are adjusted based on measured phase errors. This allows the system to compensate for manufacturing variations dynamically, reducing the need for extremely tight manufacturing tolerances while maintaining performance.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the refractive index parameters of the waveguide regions containing tunable reflectors to correct phase errors. By adjusting these optical parameters rather than physical dimensions, the system compensates for manufacturing variations without requiring re-manufacturing.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If more waveguides are added to the array to increase multiplexing capacity, then transmission capacity improves, but device area increases

Engineering Contradiction:
Improvetransmission capacityVSAvoiddevice area
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The patent combines multiple functions into the waveguide array structure itself. The same waveguides that carry optical signals also contain embedded tunable reflectors for phase correction, eliminating the need for separate correction devices and reducing overall device area.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent makes the waveguide array dynamically adjustable through tunable reflectors. This allows the device to adapt to different operating conditions and maintain optimal performance across multiple wavelengths without requiring additional static structures, thereby increasing capacity within the same footprint.

Inventive Principle:
Principle #15Dynamics

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 device effectively corrects phase errors, reducing insertion loss and crosstalk, and enables compact, efficient optical multiplexing/demultiplexing by adjusting optical path lengths using tunable reflectors and phase shifters.

Implementation Method 1

the tunable reflector is configured to act as a semi-transparent reflector for light propagating between the incident light waveguide section and the transmitted light waveguide section, thereby generating reflected light

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

each phase correcting region is configured to apply the change to correct the optical path length of the respective waveguide

Methodology Applied
Scientific EffectOptical path length adjustment:

Implementation Method 3

each pair of consecutive waveguides in the array comprises a coupler configured to: combine light propagating in the transmitted light waveguide sections of the two consecutive waveguides; determine therefrom an optical phase difference between the two consecutive waveguides

Methodology Applied
Scientific EffectOptical interference: Interference

Data Source

PatentEP4390478B1Arrayed waveguide multiplexing/demultiplexing device with phase correction
Publication Date: 2025.08.20 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)
  • EP4390478B1 patent drawingFigure 1
  • EP4390478B1 patent drawingFigure 2
  • EP4390478B1 patent drawingFigure 3

AI summary

An integrated photonics arrayed waveguide multiplexing/demultiplexing device (1) comprising: - an array (30) of waveguides (300) comprising: o an incident light waveguide section (301) comprising a phase correcting region (31); o a transmitted light waveguide section (302); o a tunable reflector (32); wherein each pair of consecutive waveguides (300) in the array (30) comprises a coupler (33) configured to: - combine light from the transmitted light waveguide sections (302); - determine therefrom an optical phase difference between the two consecutive waveguides (300); and wherein the couplers (33) are further configured to determine therefrom a change (3) in optical path length required for each of two consecutive waveguides (300) to reach a predetermined optical phase difference; and wherein each phase correcting region (31) is configured to apply the change (3) to correct the optical path length of the respective waveguide (300).