Optical Signal Splitter Asymmetric Waveguide Curvature

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Solution Overview

Problem

Existing optical signal splitters face issues with unequal signal intensity distribution due to manufacturing imprecision and wavelength variability, leading to deviations from the desired 50%/50% split ratio.

Innovation Solution

The optical signal splitter design features two waveguides with specifically curved sections, including first and second segments that are optically coupled, with differently curved sections to create a phase difference, reducing intensity differences between output signals, and utilizing a 3rd-order Bezier curve and circular arcs for minimal loss and compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional symmetric curved sections are used in both waveguides, then the splitter structure is simple and easy to manufacture, but manufacturing imprecision and wavelength variability cause unequal signal intensity distribution at the outputs

Engineering Contradiction:

Improvesignal intensity distribution equalityVSAvoidwaveguide curvature configuration

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by configuring the first curved sections of the two waveguides differently - specifically, making them have different distances from the central axis. This asymmetric design compensates for manufacturing tolerances and wavelength variations, ensuring that the optical path differences between the two waveguide paths result in equal signal intensities at the output, thereby resolving the technical contradiction between manufacturing precision and device complexity.

Inventive Principle:

Principle #4Asymmetry

2Productivity

If the waveguides are positioned closer to achieve better optical coupling, then signal splitting efficiency improves, but the device bulk increases and manufacturing precision requirements become more stringent

Engineering Contradiction:

Improvesignal splitting efficiencyVSAvoidsplitter bulk

Core Design Contradiction:

ProductivityVSVolume of stationary object

Solution Approach 1:

The patent employs curved waveguide sections with specifically designed radii of curvature to achieve efficient optical coupling between waveguides. The curved geometry allows for compact arrangement of the waveguides in a smaller volume while maintaining the necessary proximity for effective evanescent field coupling, thus improving signal splitting efficiency without significantly increasing the overall device bulk.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Adaptability or versatility

If standard curved sections are used in both waveguides, then the manufacturing process is simpler, but wavelength variations cause additional intensity differences between output signals

Engineering Contradiction:

Improvewavelength independenceVSAvoidcurved section configuration

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent applies local quality by differentiating the curvature characteristics of the first curved sections in the two waveguides. Specifically, one waveguide's first curved section has a different distance from the central axis compared to the other waveguide's corresponding section. This localized differentiation in the curved section geometry compensates for wavelength variations, making the signal splitting ratio more independent of wavelength while maintaining ease of manufacture through a systematic design approach.

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

This design achieves a consistent and equal intensity split across output signals, minimizing the impact of manufacturing variability and wavelength deviations, while maintaining low optical signal loss and compactness.

Implementation Method 1

In a central portion 104, the waveguides are closer to each other than in the rest of the splitter, and are optically coupled because of their proximity

Methodology Applied

Scientific EffectEvanescent field coupling:

Implementation Method 2

each waveguide includes between the first and second segment, starting from the first segment, a first curved section including in succession a curvature the concavity of which is turned the side opposite the axis then a curvature the concavity of which is turned towards the axis

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS10401571B2Optical signal splitter

Publication Date: 2019.09.03 STMICROELECTRONICS (CROLLES 2) SAS

AI summary

The disclosure relates to an optical splitter including two waveguides on either side of an axis. Each waveguide includes a first segment and a second segment that are closer to the axis than the rest of the waveguide. The first segments are optically coupled and the second segments are optically coupled. Each guide includes between the first and second segment, starting from the first segment, a first curved section including in succession a curvature the concavity of which is turned the side opposite the axis then a curvature the concavity of which is turned towards the axis, and starting from the second segment a second curved section including in succession a curvature the concavity of which is turned the side opposite the axis then a curvature the concavity of which is turned towards the axis. The first curved sections of the two waveguides are curved differently.