Optical Waveguide Isolator With Non-Reciprocal Phase Shift
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Solution Overview
Problem
In optical communication systems, there is a risk of damage to light sources due to return light causing interference and destabilization, which existing optical isolators using Faraday rotators do not adequately address, particularly in terms of ease of connection and component complexity.
Innovation Solution
An optical isolator with a substrate and optical waveguide having a first end part and multiple second end parts arranged in an array, featuring branching parts and non-reciprocal phase shift properties, allowing light to propagate in one direction while suppressing return light, achieved through the use of non-reciprocal members and phase shifters that provide different phase shift amounts between the end parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an optical isolator using a Faraday rotator is used, then light propagation in one direction is allowed and reverse propagation is prevented, but the device complexity and difficulty of connection to optical fibers increase
Solution Approach 1:
The optical waveguide is segmented into multiple propagation paths with different non-reciprocal phase shift amounts, allowing the isolator function to be distributed across multiple waveguide modes rather than requiring a single complex Faraday rotator component
Solution Approach 2:
The patent replaces the mechanical Faraday rotator system with an integrated optical waveguide system that uses non-reciprocal phase shifting through evanescent field coupling, eliminating the need for separate mechanical components and improving ease of connection to optical fibers
2Reliability
If an optical isolator using a Faraday rotator is used, then light propagation in one direction is allowed and reverse propagation is prevented, but the ease of connection to optical fibers deteriorates
Solution Approach 1:
The optical isolator function is merged directly into the optical waveguide structure, allowing the isolator to be integrated with optical fibers through standard waveguide coupling interfaces rather than requiring separate alignment of discrete components
Solution Approach 2:
The patent replaces the mechanical Faraday rotator system with an integrated optical waveguide system that uses non-reciprocal phase shifting through evanescent field coupling, eliminating the need for separate mechanical components and improving ease of connection to optical fibers
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 solution effectively prevents return light from entering the light source, reducing interference and destabilization, while allowing easy connection to optical fibers and minimizing component complexity, thus enhancing the reliability and efficiency of optical communication systems.
Implementation Method 1
The optical waveguide has a portion having non-reciprocity and gives different non-reciprocal phase shift amounts between the first end part and at least two of the second end parts
Data Source
AI summary
An optical isolator 10 according to the present disclosure includes a substrate 11 and an optical waveguide 12 provided on the substrate 11. The optical waveguide 12 includes a first end part 13, a plurality of second end parts 14 arranged in an array, and at least one branching part 18 located between the first end part 13 and the plurality of second end parts 14. The optical waveguide 12 has a portion having non-reciprocity and gives different non-reciprocal phase shift amounts between the first end part 13 and at least two of the second end parts 14.