Optical Waveguide Sheet Singulation for Smooth Low-Loss End Faces

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Solution Overview

Problem

Existing methods for singulating optical waveguide sheets into substrates fail to meet stringent requirements for small size, high dimensional accuracy, high end-face quality, and low-cost, high-volume production, particularly in forming substrates with non-rectangular shapes and features like cut-outs, which limits their use in commercial optical waveguide devices.

Innovation Solution

The method involves irradiating optical waveguide sheets with a focused laser beam to create modified regions that define a singulation line, allowing for precise separation of the sheets into substrates with smooth and rough sections, enabling low-loss optical coupling. This includes single irradiation, multiple pass approaches, controlled crack propagation, and post-processing to achieve optical quality surfaces and free-form shapes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional cutting methods are used to divide optical waveguide sheets, then substrates can be produced, but dimensional accuracy and end-face quality deteriorate

Engineering Contradiction:
Improvedimensional accuracy and end-face qualityVSAvoidproduction capability
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces conventional mechanical cutting methods with a laser-based modification system. The laser beam creates modified regions within the optical waveguide sheet that define singulation lines, enabling separation without mechanical contact. This substitution eliminates mechanical stress and physical contact that degrade dimensional accuracy and end-face quality, while maintaining high production capability through automated laser processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes laser parameters (wavelength, pulse duration, power, scanning speed) to precisely control the formation of modified regions. By adjusting these parameters, the system creates optimal singulation lines that enable accurate substrate separation with high dimensional precision and smooth end faces, resolving the contradiction between manufacturing precision and ease of manufacture.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If laser beam is used to create modified regions, then singulation precision is improved, but processing time increases

Engineering Contradiction:
Improvesingulation precisionVSAvoidprocessing speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent employs periodic pulsed laser action to create modified regions along singulation lines. The pulsed laser delivers energy in controlled intervals, allowing precise formation of modified regions while maintaining high processing speed. The periodic action enables the laser to scan through the optical waveguide sheet rapidly, creating evenly spaced modified regions that ensure accurate singulation without excessive processing time.

Inventive Principle:
Principle #19Periodic action

3Reliability

If optical waveguides are extended to the edge of substrate, then optical coupling is improved, but substrate strength and reliability deteriorate

Engineering Contradiction:
Improveoptical coupling efficiencyVSAvoidsubstrate structural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent creates localized modified regions along singulation lines that do not interfere with the optical waveguide structures. The laser modification is confined to specific areas between waveguides, leaving the waveguide regions intact and undisturbed. This local quality approach allows optical waveguides to extend close to substrate edges for improved optical coupling while maintaining substrate structural integrity through carefully positioned modification zones.

Inventive Principle:
Principle #3Local quality

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 method enables fast and efficient production of optical waveguide substrates with smooth end faces suitable for low-loss optical coupling, accommodating various shapes and features, thus overcoming the limitations of existing techniques and enhancing their applicability in commercial devices.

Implementation Method 1

irradiating the optical waveguide sheet with a focused laser beam to form within the body of the optical waveguide sheet modified regions

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

The optical waveguide sheet is separated along the singulation line to form an optical waveguide substrate

Methodology Applied
Scientific EffectThermal stress cracking: Fracture Mechanics

Data Source

PatentEP3969221B1Methods of singulating optical waveguide sheets to form optical waveguide substrates
Publication Date: 2024.07.17 CORNING RES & DEV CORP
  • EP3969221B1 patent drawingFigure 1A~1C
  • EP3969221B1 patent drawingFigure 1D~1E
  • EP3969221B1 patent drawingFigure 2

AI summary

The methods of singulating an optical waveguide sheet that supports sheet optical waveguides include irradiating the optical waveguide sheet with a focused laser beam comprising ultrafast light pulses to form within the body of the optical waveguide sheet modified regions, which along with unmodified regions, that define a singulation line. The modified regions define modified sections that are spaced apart by the unmodified sections, which reside at locations of the sheet optical waveguides. The optical waveguide sheet is separated along the singulation line to form an optical waveguide substrate with substrate waveguides formed by sections of the sheet optical waveguides. The optical waveguide substrate has an end face with both smooth and rough sections. The substrate waveguides have end surfaces that terminate at the smooth sections, thereby enabling low-loss optical coupling to other optical components.