Photonic Assembly With Mode-Matched Optical Isolation
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Solution Overview
Problem
Existing optical coupling methods between photonic devices and elements face challenges in ensuring unidirectional propagation of light radiation, leading to performance degradation due to parasitic reflections and mismatched mode sizes when using optical isolators.
Innovation Solution
A photonic assembly is designed with an optical isolator on one path to enforce a first mode size and adjustment means on another path to match the mode size, ensuring unidirectional propagation and optimal coupling by using blades and materials with specific optical indices to maintain equivalent mode sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an optical isolator is interposed between the photonic device and photonic element to prevent parasitic reflections, then unidirectional propagation is improved, but the mode size is altered causing mismatch and degraded coupling performance
Solution Approach 1:
A compensation element with specific optical properties (refractive index and thickness) is introduced as an intermediary component between the photonic device and photonic element. This compensation element compensates for the mode size alteration caused by the optical isolator, restoring mode size matching while maintaining the isolator's unidirectional propagation function. The compensation element acts as a mediator that balances the conflicting requirements of reflection prevention and mode matching.
2Device complexity
If conventional optical coupling methods are used without additional components, then coupling simplicity is maintained, but parasitic reflections degrade laser emission spectrum and device performance
Solution Approach 1:
The optical isolator serves as an intermediary component placed in the light path to block parasitic reflections from returning to the laser source. By introducing this unidirectional transmission element, the system prevents reflection-induced degradation of the laser emission spectrum while maintaining acceptable coupling performance through the additional compensation element.
3Reliability
If the optical isolator is placed on one path to enforce mode size, then unidirectional propagation is achieved, but the other path lacks mode size control causing coupling optimization issues
Solution Approach 1:
The solution employs asymmetric treatment of the two optical paths: the first path contains both the optical isolator and compensation element for unidirectional propagation and mode control, while the second path contains only the compensation element for mode size matching. This asymmetric configuration allows each path to be optimized for its specific functional requirements while maintaining overall system balance.
Solution Approach 2:
The compensation element is strategically placed on both paths as an intermediary component that specifically addresses mode size matching. On the first path, it works in conjunction with the optical isolator, while on the second path, it independently provides the necessary mode size control to achieve optimal coupling without requiring an additional isolator.
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 parasitic reflections, maintains unidirectional light propagation, and optimizes coupling performance by aligning mode sizes, thereby enhancing the photonic device's efficiency and reducing performance degradation.
Implementation Method 1
an optical isolator interposed on a path of light propagation, called a first path, between at least one first output and at least one second input, and imposing on a radiation, propagating along the first path, a first mode size
Implementation Method 2
adjustment means interposed on a path of light propagation, called a second path, between at least one first input and at least one second output, the adjustment means being configured to impose on a radiation, propagating along the second path, a second mode size equal to the first mode size
Implementation Method 3
there are situations where ensuring unidirectional propagation of light radiation during its extraction from the photonic device is desirable. Indeed, radiation extracted from a photonic device is susceptible to reflection, and thus some of it may be reinjected into the photonic device and ultimately into the laser that produced it
Data Source
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AI summary
The invention relates to a photonic assembly (100) which comprises: - a photonic device (200a) comprising an exit guide (207a) and an entry guide (208a) respectively collaborating with a first exit (202a) and a first entrance (203a); - a photonic element (200b) provided with a second exit (203b) and with a second entrance (202b) which are optically coupled with the first entrance (203a) and the first exit (202a); - an optical isolator (250) interposed in the path between the first exit (202a) and the second entrance (202b), and imposing a first size on the radiation travelling along the first path; - adjustment means (260) interposed on the path between the first entrance (203a) and the second exit (203b), the adjustment means (260) being configured to interpose a second size, equal to the first size, on the radiation travelling along the second path.