Optical Isolator Laser Crystallization to Reduce Circuit Heating

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Solution Overview

Problem

Existing optical isolators with magneto-optic material waveguides face challenges in achieving sufficient non-reciprocity in the non-reciprocal member without adversely affecting the electronic circuit due to heating during crystallization, leading to potential changes in circuit characteristics.

Innovation Solution

A method involving selective laser irradiation of the non-reciprocal member to crystallize a portion in contact with the waveguide while minimizing exposure to the electronic circuit, ensuring weak non-reciprocity in areas near the circuit and strong non-reciprocity where needed, using a mask to control laser light distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the non-reciprocal member is fully crystallized to achieve strong non-reciprocity, then the isolator performance is improved, but the electronic circuit is adversely affected by heating during crystallization

Engineering Contradiction:

Improveisolator performanceVSAvoidthermal influence on electronic circuit

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating different crystallization states in different regions of the non-reciprocal member. The region near the waveguide is fully crystallized to provide strong non-reciprocity for isolator function, while the region near the electronic circuit remains amorphous to minimize thermal influence. This spatial variation in material state resolves the contradiction between achieving strong non-reciprocity and protecting the electronic circuit from heating.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The non-reciprocal member is segmented into functionally distinct regions: a first region with strong non-reciprocity for optical isolation and a second region with weak non-reciprocity near the electronic circuit. This segmentation allows each region to be optimized for its specific function, with the crystallization process selectively applied to only the necessary portion.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If laser irradiation is applied to crystallize the non-reciprocal member, then the non-reciprocity is enhanced, but the electronic circuit characteristics may change due to heating

Engineering Contradiction:

Improvecrystallization controlVSAvoidcircuit characteristics

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The laser irradiation is applied locally only to the region of the non-reciprocal member that requires crystallization for isolator function. By controlling the laser beam spatial distribution, the patent achieves precise crystallization in the first region while leaving the second region near the electronic circuit amorphous, thus maintaining circuit characteristics while achieving the necessary non-reciprocity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of irradiating the entire non-reciprocal member, the patent applies partial action by irradiating only the specific region that requires crystallization. This partial irradiation approach achieves the necessary non-reciprocity while avoiding unnecessary heating of other regions, particularly protecting the electronic circuit from thermal effects.

Inventive Principle:

Principle #16Partial or excessive action

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 effectively crystallizes the non-reciprocal member to achieve necessary phase shifts while reducing thermal influence on the electronic circuit, enhancing isolator performance and reducing potential circuit changes.

Implementation Method 1

irradiating a region of the non-reciprocal member with laser light

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

crystallize a portion in contact with the waveguide

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Implementation Method 3

achieve necessary phase shifts

Methodology Applied

Scientific EffectFaraday effect: Faraday Effect

Data Source

PatentUS12422703B2Isolator and isolator manufacturing method

Publication Date: 2025.09.23 KYOCERA CORP

AI summary

An isolator includes a substrate, a waveguide and an electronic circuit disposed above the substrate, and a non-reciprocal member disposed above the waveguide and the electronic circuit. The non-reciprocal member includes a first portion in contact with the waveguide and a second portion disposed within a predetermined range from the electronic circuit. Non-reciprocity in the second portion is weaker than non-reciprocity in the first portion.