Optical Isolator Waveguide Non-reciprocal Member Design
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Solution Overview
Problem
Existing optical isolators face challenges in efficiently facilitating the propagation of electromagnetic waves in one direction while hindering their propagation in the opposite direction, often resulting in high loss and size constraints due to complex reciprocal and non-reciprocal phase shifters.
Innovation Solution
The design incorporates a first waveguide and a second waveguide on a substrate, where the second waveguide includes a non-reciprocal member, allowing for different coupling coefficients based on the direction of electromagnetic wave propagation, thereby optimizing transmittance and reducing loss by using a simpler structure that overlaps or is arranged alongside the first waveguide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex reciprocal and non-reciprocal phase shifters are used to facilitate electromagnetic wave propagation in one direction while hindering it in the opposite direction, then the isolator's directional control capability is improved, but the device complexity and size increase
Solution Approach 1:
The patent extracts and eliminates the complex reciprocal phase shifter from the traditional isolator structure, retaining only the essential non-reciprocal phase shifter combined with waveguides. This extraction maintains the core directional control function while removing unnecessary complexity, directly resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The patent merges the non-reciprocal phase shifter with the waveguide structure, creating an integrated design where the phase shifter is embedded within or alongside the waveguide paths. This merging reduces the number of discrete components and simplifies the overall structure while preserving directional control capability.
2Reliability
If complex reciprocal and non-reciprocal phase shifters are used to achieve directional electromagnetic wave control, then the isolator's functionality is improved, but the loss increases
Solution Approach 1:
By removing the reciprocal phase shifter from the structure, the patent eliminates the additional interfaces and components that would introduce loss. The simplified structure with fewer elements reduces reflection, scattering, and absorption losses while maintaining the essential directional control function through the non-reciprocal phase shifter alone.
3Device complexity
If a simpler waveguide structure with non-reciprocal member is used, then the device complexity is reduced, but the directional control effectiveness may be compromised
Solution Approach 1:
The patent introduces a non-reciprocal member with asymmetric properties into the waveguide structure. This asymmetry creates different propagation characteristics for forward and backward traveling waves, enabling effective directional control. The asymmetric design ensures that while the overall structure remains simple, the directional control effectiveness is maintained through the inherent non-reciprocal properties of the asymmetric component.
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 configuration effectively enhances the isolator's ability to preferentially transmit electromagnetic waves in one direction over the other, reducing loss and enabling compact integration by simplifying the structure, thus improving the isolator's functionality and size efficiency.
Implementation Method 1
The core of the second waveguide includes a non-reciprocal member in at least one part of a cross section intersecting a direction in which the second waveguide extends
Data Source
AI summary
An isolator includes a first waveguide and a second waveguide on a substrate having a substrate surface, the first waveguide and the second waveguide located along the substrate surface and overlapping each other as viewed from the substrate. The first waveguide and the second waveguide each include a core and a clad. The core has a first surface facing the substrate surface, and a second surface opposite to the first surface. The clad contacts the first surface and the second surface of the core. The first waveguide has a first end and a second end, and has a port for input and output of electromagnetic waves at each of the first end and the second end. The core of the second waveguide includes a non-reciprocal member in at least one part of a cross section intersecting a direction in which the second waveguide extends.