Optical Connector System With Convex Lenses For Grating Coupler Alignment
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Solution Overview
Problem
The challenge is to achieve high-accuracy optical connection between single-mode optical fibers and grating couplers, which is critical for maintaining signal integrity and transmission efficiency, especially in data centers where signal degradation and misalignment can occur due to the small core diameter and vulnerability to bending of single-mode fibers.
Innovation Solution
An optical connector system is designed with an optical path-changing device that holds the single-mode optical fiber and includes a reflection surface, coupled with a relay device on a substrate having a grating coupler, both equipped with convex lenses to input/output collimated light and change the optical signal direction, minimizing aberration and thermal expansion issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single-mode optical fibers are used to achieve long transmission distance and high transmission speed, then signal degradation is reduced, but alignment accuracy requirements increase significantly
Solution Approach 1:
The patent introduces a grating coupler as an intermediary device between the optical fiber and the optical waveguide. The grating coupler converts the optical signal from the fiber into a diffracted beam that can be coupled into the waveguide, acting as a mediator that bridges the gap between fiber and chip-scale photonic circuits. This intermediary structure enables single-mode fiber connection without requiring extremely tight lateral alignment tolerances.
Solution Approach 2:
The patent employs parameter changes in the grating coupler design, specifically adjusting the grating period, depth, and orientation to optimize the coupling efficiency between single-mode fibers and the optical waveguide. By changing the grating parameters, the system achieves high coupling efficiency while maintaining relaxed alignment tolerances, thus resolving the contradiction between transmission quality and alignment precision requirements.
2Adaptability or versatility
If grating couplers are used to couple optical signals, then fiber-to-chip coupling is enabled, but optical signal direction becomes inclined relative to substrate normal
Solution Approach 1:
The patent addresses the inclined optical path by introducing a reflective element that redirects the diffracted beam. Instead of accepting the inclined output direction of the grating coupler, the system uses a mirror or reflective waveguide to change the propagation direction, effectively adding a dimensional transformation to the optical path. This allows the grating coupler to maintain its coupling advantage while the final optical path becomes perpendicular to the substrate.
3Ease of manufacture
If conventional optical connection structures are used, then manufacturing is simpler, but thermal expansion causes misalignment and signal loss
Solution Approach 1:
The patent applies local quality by creating a specialized thermal management region around the grating coupler and optical connection points. This includes using materials with matched thermal expansion coefficients in critical alignment areas, and designing the substrate with localized thermal compensation structures. The bulk substrate can be manufactured simply, but critical local regions have enhanced thermal stability properties to prevent misalignment.
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 enables precise and stable optical coupling between the grating coupler and single-mode optical fiber, reducing signal loss and maintaining high accuracy even under varying thermal conditions, thus enhancing transmission efficiency and reducing manufacturing complexities.
Implementation Method 1
inputting/outputting collimated light of the optical signal between the convex lens of the optical path-changing device and the convex lens of the relay device
Implementation Method 2
a reflection surface configured to reflect an optical signal
Implementation Method 3
a grating coupler for inputting/outputting an optical signal in a second direction that is inclined with respect to a direction perpendicular to a surface of the substrate
Data Source
AI summary
An optical connector system includes: an optical path-changing device including a fiber-holding part that holds a single-mode optical fiber along a first direction, and a reflection surface that reflects an optical signal; and a relay device on a substrate. The substrate includes a grating coupler for inputting/outputting an optical signal in a second direction that is inclined with respect to a direction perpendicular to a surface of the substrate. The optical path-changing device and the relay device each have an input/output surface to/from which the optical signal is inputted/outputted. A first convex lens is disposed on the input/output surface of the optical path-changing device. A second convex lens is disposed on the input/output surface of the relay device.