Optical Fiber Coupler Using PLC Waveguides for Compact Transceivers
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Solution Overview
Problem
Existing optical fiber couplers for optical transceivers face challenges in miniaturization and cost reduction due to light intensity loss and increased size, especially when multiple channels are integrated, leading to larger horizontal dimensions and inefficiencies in optical signal transmission.
Innovation Solution
The use of silica-based planar lightwave circuit (PLC) technology to form optical waveguide patterns at specific angles, allowing for a 1:1 correspondence between optical fibers and PLC waveguides, which are then integrated with photonics chips, enabling pitch transformation and reducing the number of optical fibers through the inclusion of functional devices like splitters, combiners, and demultiplexers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If directly bending multiple optical fibers using a structure bent at a certain angle is used, then the optical fiber coupler can be formed, but light intensity loss occurs when the bending radius is less than the recommended radius of curvature
Solution Approach 1:
The patent replaces the mechanical bending of optical fibers with an optical waveguide structure that uses refraction and total internal reflection principles. Instead of physically bending fibers at risky angles, the invention uses a planar lightwave circuit with controlled refractive indices to guide and couple light between fibers, eliminating bending loss while maintaining manufacturing feasibility.
Solution Approach 2:
The patent introduces an optical waveguide as an intermediary component between optical fibers. This waveguide structure acts as a mediator that transfers optical signals without requiring direct fiber bending, thus preventing light intensity loss while enabling the coupler functionality.
2Ease of manufacture
If the optical fiber coupler is designed with a large center distance between channels, then manufacturing is easier, but the overall size becomes large in both vertical and horizontal directions
Solution Approach 1:
The patent transitions from a two-dimensional layout to a three-dimensional structure by stacking multiple optical waveguides in layers. This vertical arrangement allows channels to be positioned closer in the horizontal plane while maintaining adequate separation through vertical layering, thus reducing the overall footprint while preserving manufacturing ease.
Solution Approach 2:
The patent employs a nested structure where multiple optical waveguides are arranged in concentric or layered configurations. This nesting allows efficient use of space by placing waveguides at different radial distances or vertical levels, reducing the coupler's horizontal and vertical dimensions while maintaining manufacturability.
3Productivity
If multiple channels are integrated in a large-capacity photonics chip, then data transmission capacity increases, but the optical fiber coupler size increases in the horizontal direction
Solution Approach 1:
The patent addresses the horizontal size increase by moving channels into the vertical dimension through multi-layer waveguide stacking. This allows high-density channel integration without proportionally increasing the horizontal footprint, enabling high data transmission capacity in a compact form factor.
Solution Approach 2:
The patent merges multiple optical channels into a unified planar lightwave circuit structure where waveguides share common coupling regions and support structures. This consolidation reduces redundant spacing and minimizes the horizontal dimension while supporting multiple high-capacity channels.
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 allows for a compact, multifunctional, and cost-effective optical fiber coupler that maintains a constant center-to-center distance between fibers, reduces bending loss, and enables flexible channel spacing, thereby addressing the limitations of traditional couplers in high-density optical transceivers.
Implementation Method 1
an optical waveguide block including a plurality of optical waveguides coupled to the plurality of optical fibers, respectively, and configured to transfer optical signals transmitted through the plurality of optical fibers connected to the optical FAB in a second direction in which a photonics chip is placed and which is different from the first direction
Implementation Method 2
the optical waveguides of the optical waveguide block may be bent at a specific angle such that the optical signals are optically coupled using a surface optical coupler of the silicon-based photonics chip
Implementation Method 3
forming a plurality of optical waveguide patterns with a specific angle such that one side of a PLC optical waveguide is optically coupled at a certain angle
Implementation Method 4
applying technology of directly bending multiple optical fibers using a structure bent at a certain angle. An allowable minimum bending radius of a general single-mode optical fiber may have a value of about 10 mm
Data Source
AI summary
An optical fiber coupler includes a plurality of optical fibers parallel to each other in a first direction, an optical fiber array block (FAB) configured to maintain a constant center-to-center distance between the plurality of optical fibers, and an optical waveguide block including a plurality of optical waveguides coupled to the plurality of optical fibers, respectively, and configured to transfer optical signals transmitted through the plurality of optical fibers connected to the optical FAB in a second direction in which a photonics chip is placed and which is different from the first direction.