Optical Branching Element Tapered Waveguide Loss Reduction

Solution Overview

Problem

Conventional optical branching elements using strip-like waveguides fail to achieve desired loss reduction in some cases, necessitating a more effective design to minimize optical loss.

Innovation Solution

An optical branching element comprising an input waveguide, a tapered waveguide, two branched waveguides forming a Y-shape, and a series of strip-like waveguides connecting the branched waveguides without protruding outside, with widths decreasing as they move away from the tapered waveguide, and a buffer waveguide that decreases in height, enhancing coupling efficiency and reducing optical loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If strip-like waveguides are provided in conventional optical branching elements, then loss reduction is predicted from design, but desired loss reduction is not achieved in actual fabrication

Engineering Contradiction:

Improveoptical lossVSAvoidwaveguide pattern deformation

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The patent applies local quality by making the strip-like waveguides asymmetric in their connection to the branched waveguides. Specifically, the strip-like waveguides are configured to be connected to only one of the two branched waveguides rather than symmetrically connecting both, creating localized structural differences that prevent pattern deformation while maintaining loss reduction benefits

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention implements asymmetry by designing strip-like waveguides with unequal connection characteristics to the branched waveguides. The strip-like waveguides have different geometrical relationships with each branched waveguide, breaking the symmetric structure that causes fabrication-induced pattern deformation and enabling both low loss and manufacturing precision

Inventive Principle:

Principle #4Asymmetry

2Reliability

If strip-like waveguides are provided to reduce loss, then coupling efficiency should improve, but waveguide pattern deformation occurs preventing desired performance

Engineering Contradiction:

Improvecoupling efficiencyVSAvoidwaveguide pattern accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by making the strip-like waveguides asymmetric in their connection to the branched waveguides. Specifically, the strip-like waveguides are configured to be connected to only one of the two branched waveguides rather than symmetrically connecting both, creating localized structural differences that prevent pattern deformation while maintaining loss reduction benefits

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention implements asymmetry by designing strip-like waveguides with unequal connection characteristics to the branched waveguides. The strip-like waveguides have different geometrical relationships with each branched waveguide, breaking the symmetric structure that causes fabrication-induced pattern deformation and enabling both low loss and manufacturing precision

Inventive Principle:

Principle #4Asymmetry

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 design significantly reduces optical loss by improving coupling efficiency and preventing deformation of waveguide patterns, achieving closer alignment with the designed loss reduction values.

Implementation Method 1

a tapered waveguide connected to the input waveguide; two branched waveguides that are connected to the tapered waveguide

Methodology Applied

Scientific EffectTapered waveguide mode transformation: Waveguide (optics)

Implementation Method 2

a plurality of strip-like waveguides that are provided so as to connect between the two branched waveguides and not to protrude outside the two branched waveguides

Methodology Applied

Scientific EffectEvanescent field coupling: Waveguide (optics)

Data Source

PatentUS8718423B2Optical branching element and optical branching circuit

Publication Date: 2014.05.06 FURUKAWA ELECTRIC CO LTD

AI summary

An optical branching element includes: an input waveguide; a tapered waveguide connected to the input waveguide; two branched waveguides that are connected to the tapered waveguide and arranged so as to form a Y-shape with the input waveguide and the tapered waveguide; and a plurality of strip-like waveguides that are provided so as to connect between the two branched waveguides and not to protrude outside the two branched waveguides, and formed so as to decrease in width as becoming distant from the tapered waveguide.