Optical Waveguide Layout for TM-Mode Non-Reciprocity Control
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Solution Overview
Problem
Existing optical isolators using magneto-optical materials like Ce: YIG face challenges in controlling non-reciprocity and waveguide losses, particularly in TM mode electromagnetic waves, leading to unintended non-reciprocity and energy leakage.
Innovation Solution
The optical integrated circuit design includes a substrate with waveguides and non-reciprocal members positioned within or outside the mode field diameter of TM mode electromagnetic waves to control non-reciprocity, using materials like Ce: YIG, ensuring precise placement to manage energy distribution and minimize leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-reciprocal member is placed in the waveguide to achieve non-reciprocal isolation, then isolation performance is improved, but waveguide losses increase and unintended non-reciprocity occurs
Solution Approach 1:
The patent applies local quality by placing the non-reciprocal member only in the first waveguide where non-reciprocal isolation is desired, while leaving the second waveguide without such a member. This selective placement achieves intended isolation functionality while avoiding unintended non-reciprocity and energy losses in other waveguides, resolving the contradiction between isolation performance and waveguide losses.
2Reliability
If the non-reciprocal member is positioned closer to the waveguide core to enhance non-reciprocity, then isolation effect is improved, but energy leakage increases
Solution Approach 1:
The patent resolves the contradiction by transitioning from a single-dimensional placement approach to a multi-dimensional positioning strategy. The non-reciprocal member is positioned at specific distances from the waveguide core in the vertical dimension, and the waveguide structure extends in the horizontal dimension. This dimensional approach allows optimization of both isolation effect and energy leakage by controlling the spatial relationship between the non-reciprocal member and the waveguide mode field distribution.
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 effectively controls non-reciprocity and reduces energy leakage, enabling intended operation of the optical isolator, protecting optical sources and enhancing transmission efficiency.
Implementation Method 1
a known optical isolator includes a layer of magneto-optical material Ce: YIG as a waveguide layer
Data Source
AI summary
An optical integrated circuit includes a substrate including a substrate surface, a first waveguide and a second waveguide configured to allow electromagnetic waves to propagate along the substrate surface, and a non-reciprocal member disposed on a side of the first waveguide and the second waveguide remote from the substrate surface. At least part of the non-reciprocal member is disposed in a range of a mode field diameter of TM mode electromagnetic waves in the first waveguide. The non-reciprocal member is not disposed in a range of a mode field diameter of TM mode electromagnetic waves in the second waveguide.