Optical Semiconductor Waveguide Curvature Design

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Solution Overview

Problem

In optical semiconductor devices with 90-degree hybrid circuits, curved waveguides cause light loss and higher order mode issues due to discontinuities in intensity distribution, leading to increased design and layout creation times and potential abnormal growth during embedding.

Innovation Solution

The optical semiconductor device features input and output waveguides with specific curving portions, where the central axis of the first curving portion is inwardly offset from the straight portion, and the second curving portion follows a raised sine curve, reducing light loss and higher order mode occurrences while simplifying design calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If curved waveguides are used in optical semiconductor devices, then the device can be compact and routing is flexible, but light loss increases and higher order mode issues occur due to discontinuities in intensity distribution

Engineering Contradiction:

Improvedevice sizeVSAvoidlight loss

Core Design Contradiction:

Volume of moving objectVSLoss of energy

Solution Approach 1:

The patent applies curvature to the waveguide central axis, specifically using an S-shaped curve with inward offset in the first curving portion and raised sine curve in the second curving portion. This controlled curvature design allows the waveguide to achieve compact routing while managing light propagation characteristics to reduce loss and mode issues.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent applies different curvature characteristics to different portions of the waveguide. The first curving portion has inward offset with central axis displacement, while the second curving portion follows raised sine curve. This local differentiation optimizes light propagation in each section, reducing overall light loss while maintaining compact device size.

Inventive Principle:

Principle #3Local quality

2Device complexity

If curved waveguides with discontinuous intensity distribution are used, then device complexity is reduced, but manufacturing precision deteriorates due to abnormal growth during embedding

Engineering Contradiction:

Improvewaveguide structure complexityVSAvoidembedding precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The S-shaped curved path with controlled offsets provides a predictable geometric pattern that simplifies the overall waveguide structure while ensuring continuous intensity distribution. This regular curved geometry is easier to manufacture with precision compared to arbitrary complex paths.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameters of the curved portions systematically - using inward offset for the first curving portion and raised sine curve for the second. These parameter changes create a structure that is both simple to design and precise to manufacture, avoiding abnormal growth during embedding.

Inventive Principle:

Principle #35Parameter changes

3Loss of time

If traditional curved waveguide designs are used, then design time is reduced, but light loss and higher order mode occurrences increase

Engineering Contradiction:

Improvedesign timeVSAvoidlight loss

Core Design Contradiction:

Loss of timeVSLoss of energy

Solution Approach 1:

The patent employs S-shaped curves with mathematically defined characteristics (inward offset and raised sine curve) that can be directly implemented in design software. This approach provides a ready-to-use design template that reduces design time while inherently minimizing light loss and higher order mode issues through the continuous intensity distribution.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

By changing the waveguide central axis parameters to follow specific curved paths with controlled offsets, the design achieves optimal light propagation characteristics without requiring extensive optimization iterations, thus reducing design time while minimizing light loss.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10859766B2Optical semiconductor device

Publication Date: 2020.12.08 SUMITOMO ELECTRIC DEVICE INNOVATIONS

AI summary

An optical semiconductor device comprises a semiconductor substrate, an optical 90-degree hybrid circuit provided on the substrate, a plurality of input optical waveguides provided on the substrate, and a plurality of output optical waveguides provided on the substrate. The plurality of input optical waveguides is optically coupled to input ends of the optical 90-degree hybrid circuit. The plurality of output optical waveguides is optically coupled to output ends of the optical 90-degree hybrid circuit. Each of the plurality of input optical waveguides includes a first curving portion and a first straight portion adjacent to the first curving portion, and each of the plurality of output optical waveguides includes a second curving portion. A central axis of the first curving portion is inwardly offset with respect to a central axis of the first straight portion, and a central axis of the second curving portion follows a raised sine curve.