Multi-Channel Optical Isolator Assembly With GRIN Lens Alignment
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Solution Overview
Problem
The challenge of creating compact, low-loss, and cost-effective optical isolators for high-density optical channel counts in semiconductor dies is exacerbated by the need for tight mechanical alignment and assembly of free space and optical fiber coupled elements, leading to instability and data transmission errors due to uncontrolled optical reflection.
Innovation Solution
The development of multi-channel optical isolator assemblies using gradient index (GRIN) lens arrays and index-matching epoxy, combined with passive alignment features such as V-shaped grooves and alignment pins, allows for compact and efficient integration of optical isolators with single-mode fibers, reducing insertion loss and enabling higher channel counts without increasing device footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional optical isolators are used with single-mode laser arrays, then optical isolation is achieved, but the device footprint increases and mechanical alignment becomes complex
Solution Approach 1:
The patent combines multiple optical isolator functions into a single integrated device that serves multiple channels simultaneously. The optical isolator assembly integrates free-space optical components and fiber-coupled components in one unified structure, eliminating the need for separate isolators for each channel and reducing the overall device footprint while maintaining optical isolation reliability.
Solution Approach 2:
The patent employs a nested structure where fiber arrays are coupled to GRIN lenses which are in turn coupled to free-space optical components. This nested arrangement allows compact packaging of multiple optical elements within a small footprint, with each layer serving a specific function in the optical path while maintaining efficient space utilization.
2Reliability
If traditional optical isolators are assembled individually, then optical isolation is achieved, but manufacturing time and cost increase
Solution Approach 1:
The patent merges multiple optical isolator assemblies into a single integrated unit that can be manufactured as one piece or pre-assembled module. This allows for batch manufacturing and reduces the need for individual alignment and assembly of separate isolators, significantly improving production efficiency while maintaining optical isolation performance.
Solution Approach 2:
The patent incorporates preliminary alignment features and pre-assembled subcomponents that enable rapid final assembly. The optical elements are pre-positioned and pre-aligned during manufacturing, allowing for quick integration into the final device without time-consuming active alignment processes, thus improving productivity.
3Reliability
If free space and optical fiber coupled elements are combined, then optical isolation is achieved, but mechanical alignment tolerances become tight
Solution Approach 1:
The patent introduces GRIN (Gradient Index) lenses as intermediary elements between the fiber arrays and free-space optical components. These GRIN lenses serve as coupling intermediaries that relax the alignment tolerances by providing a gradual transition between the fiber mode fields and free-space beams, reducing the sensitivity to misalignment while maintaining effective optical isolation.
Solution Approach 2:
The patent utilizes GRIN lenses with specific gradient index parameters to transform the optical beam parameters (divergence, waist size) between fiber and free-space domains. By carefully selecting the GRIN lens parameters (gradient constant, length, aperture), the system achieves robust coupling with relaxed alignment tolerances while maintaining optical isolation effectiveness.
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 approach results in reduced insertion loss, lower electrical power consumption, and improved optical link power budget, enhancing data transmission stability and efficiency in high-density optical interconnects.
Implementation Method 1
magneto-optic crystals
Implementation Method 2
gradient index (GRIN) lens arrays
Data Source
AI summary
Multichannel optical assemblies for optical IO (input output) systems are provided. The optical assemblies comprise an optical isolator. In some examples the optical assemblies also comprise an array of GRIN lenses. In other examples, the optical assemblies also comprise micromirrors.