Optical Isolator Chip With Inclined Surface for Compact Beam Shift

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Solution Overview

Problem

Existing optical isolators in laser modules for optical communication face challenges in achieving a small device size while maintaining a large beam shift without degrading optical characteristics, often leading to increased size and material waste due to the need for adjusting optical axes, which complicates high-density mounting.

Innovation Solution

An optical axis shift type optical isolator is designed with an incident surface inclined at 40° or less relative to the incident light axis, ensuring a shift length difference of ΔT - ΔC ≤ 0.10 mm, integrating polarizers and Faraday rotators to maintain effective diameter and optical characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the incident surface is processed perpendicular to the chip axis and the chip is arranged at an inclination angle of 2 to 6 degrees, then the optical axis shift is achieved, but the device size increases due to the need to secure effective diameter

Engineering Contradiction:
Improveoptical axis shiftVSAvoiddevice size
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The incident surface is processed with an asymmetric inclination angle of 40 degrees or less relative to the incident light axis, rather than being perpendicular to the chip axis. This asymmetric configuration enables the optical isolator to achieve the required optical axis shift while maintaining a compact device size, resolving the contradiction between optical performance and device volume.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The inclination angle of the incident surface is optimized to 40 degrees or less relative to the incident light axis, which is a specific parameter change from the conventional perpendicular arrangement. This parameter optimization allows the device to achieve both the required beam shift and a reduced effective diameter, simultaneously improving optical performance and reducing device size.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the incident surface is pre-processed with inclination and the chip is installed on a base with magnet, then the optical axis shift is achieved, but the device complexity increases due to additional components

Engineering Contradiction:
Improveoptical axis shiftVSAvoidstructure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The incident surface is processed with an asymmetric inclination angle of 40 degrees or less relative to the incident light axis. This asymmetric design achieves the optical axis shift function through geometric configuration alone, eliminating the need for additional magnets or complex mounting bases, thereby reducing device complexity while maintaining optical performance.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The magnet and complex mounting base components are extracted from the device structure. The optical axis shift function is achieved solely through the inclined incident surface geometry, simplifying the overall device structure while maintaining the required optical functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the chip height is enlarged to secure effective diameter, then the optical characteristics are maintained, but the material waste increases

Engineering Contradiction:
Improveoptical characteristicsVSAvoidmaterial waste
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The inclination angle of the incident surface is optimized to 40 degrees or less relative to the incident light axis. This parameter optimization enables the device to maintain maximum effective diameter and excellent optical characteristics without unnecessarily enlarging the chip height, thereby reducing material consumption and waste.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of uniformly enlarging the entire chip height, the solution applies the inclined surface configuration only where necessary to achieve the required effective diameter. This partial action approach maintains optical characteristics while minimizing material usage and reducing waste.

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 optical isolator achieves a small device size with a large beam shift and maintains maximum effective diameter without degrading optical performance, allowing for simpler structure and reduced material waste.

Implementation Method 1

an optical isolator is used, which includes a Faraday rotator to rotate a polarization plane in a non-reciprocal manner

Methodology Applied
Scientific EffectFaraday effect: Faraday Effect

Implementation Method 2

one or more polarizers and one or more Faraday rotators arranged in a direction of light travel

Methodology Applied
Scientific EffectPolarization: Polarisation

Data Source

PatentEP4644971A1Optical isolator and optical isolator manufacturing method
Publication Date: 2025.11.05 SHIN ETSU CHEMICAL CO LTD
  • EP4644971A1 patent drawingFigure 1~2
  • EP4644971A1 patent drawingFigure 3~4
  • EP4644971A1 patent drawingFigure 5~6

AI summary

The present invention is an optical axis shift type optical isolator including a polarizer and a Faraday rotator and an optical isolator chip in which the polarizer and the Faraday rotator are bonded and integrated to form the optical isolator chip, in which an incident surface of the optical isolator chip is a surface inclined at an angle of 40° (degrees) or less with respect to an optical axis of incident light toward the optical isolator, the incident surface of the optical isolator chip is a surface inclined with respect to a central axis of the optical isolator chip in the direction of light travel, the central axis of the optical isolator chip is inclined with respect to the optical axis of the incident light toward the optical isolator, a shift length ΔT (mm) between the optical axis of the incident light toward the optical isolator and an optical axis of emitted light from the optical isolator and an inclination displacement length ΔC (mm) between an emission surface side and an incident surface side of the optical isolator chip, satisfy |ΔT - ΔC| ≤ 0.10 (mm). This provides the optical isolator that can obtain a large amount of beam shift without degrading the optical characteristics of the optical isolator, while being small in optical device size.