Lateral Current Injection in Integrated Optical Isolators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical devices with integrated semi-conductor laser emission sources and optical isolators face issues such as significant optical and electrical losses due to the proximity of electrical contact layers to the active zone, leading to local heating and technological production challenges, which compromise the integration and performance of these devices.
Innovation Solution
The optical isolator design decouples current injection from the magneto-optical components by removing the electrical contact layer above the active zone, allowing current injection via the lateral faces and edges, thereby reducing optical losses and improving thermal management, while maintaining the buried stripe structure for integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the electrical contact layer is placed close to the active zone for current injection, then the electrical connection is improved, but optical losses and electrical losses increase significantly
Solution Approach 1:
The patent transitions from vertical current injection (through the contact layer above the active zone) to lateral current injection (through the contact layer at the sides of the active zone). This dimensional change allows the contact layer to be positioned laterally adjacent to the active zone rather than directly above it, reducing optical interference while maintaining electrical connection.
Solution Approach 2:
The patent introduces a buried stripe structure as an intermediary between the contact layer and the active zone. This buried stripe serves as a lateral current path that conducts electricity from the contact layer to the active zone without requiring the contact layer to be positioned directly above the active zone, thereby reducing optical losses while maintaining effective current injection.
2Ease of operation
If the electrical contact layer is placed close to the active zone, then current injection is facilitated, but local heating increases due to electrical losses
Solution Approach 1:
By changing from vertical to lateral current injection geometry, the patent reduces the overlap between the contact layer and active zone, thereby reducing electrical losses and the associated local heating while maintaining effective current delivery to the active zone.
3Loss of energy
If the electrical contact layer is removed above the active zone, then optical losses are reduced, but current injection becomes more complex
Solution Approach 1:
The patent resolves the complexity issue by using the buried stripe structure to guide lateral current flow to the active zone. This maintains relatively simple current injection geometry while achieving the optical benefits of removing the contact layer above the active zone.
4Reliability
If traditional optical isolator components are integrated, then optical isolation function is achieved, but device dimensions increase making integration difficult
Solution Approach 1:
The patent combines the optical isolator and laser source into a single integrated structure where the laser source serves dual functions as both the light source and the optical isolator. This merging eliminates the need for separate isolator components, achieving optical isolation while maintaining compact dimensions suitable for integration.
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 enhances optical isolation and amplification performance by minimizing electrical and optical losses, improving the integration and production feasibility of the opto-electronic device without the drawbacks of previous configurations.
Implementation Method 1
The best known is the Faraday effect. Subjected to an external magnetic field, certain so-called magneto-optical materials rotate the plane of polarization of the light in a different direction according to the direction of propagation of the light.
Implementation Method 2
In the presence of a magnetic field symbolized by a black arrow, according to the direction of propagation of the light symbolized by a straight barred arrow, the index n becomes n↑ in a first direction of propagation and n↓ in the opposite direction. The difference between the two imaginary parts I.P. of the indices n↑ and n↓ gives the isolation ratio I.R.
Data Source
AI summary
The field of the invention is that of optical devices comprising an integrated semi-conductor laser and an integrated optical isolator. These devices are used mainly in the field of digital telecommunications. More particularly, the invention applies to so-called absorption isolators whose complex index is non-reciprocal and depends on the direction of propagation of the light. Generally, integrated optical isolators of this type fulfill two functions. On the one hand, they comprise a magneto-optical layer ensuring the non-reciprocal effect and on the other hand an active zone ensuring the amplification of the laser beam, the injection of the charge carriers into the active zone being ensured by an electrical contact layer. The invention proposes, so as to limit the disturbing effects of the contact layer on the propagation of the laser beam, that the contact layer be eliminated above the active zone and that the injection of the charge carriers be ensured via the lateral faces and the edges of the upper face of the active zone.