Optical Module Reducing Connection Loss via Intermediary Transformer
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Solution Overview
Problem
The integration of silicon thin-wire waveguides with single-mode optical fibers is hindered by significant connection losses due to differences in mode field diameters, and existing solutions complicate manufacturing and reduce yield.
Innovation Solution
An optical module configuration that includes a single-mode optical fiber, a high relative refractive-index difference optical fiber, a planar lightwave circuit with a quartz-based glass core and cladding, and a silicon thin-wire waveguide, where the relative refractive-index differences are optimized to minimize connection losses through fusion splicing and adhesive fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a special structure is provided at the end of the silicon thin-wire waveguide to adjust the mode field diameter, then connection loss is reduced, but manufacturing process becomes complicated
Solution Approach 1:
The patent introduces an optical transformer as an intermediary component between the single-mode optical fiber and the silicon thin-wire waveguide. This transformer includes a first optical waveguide connected to the optical fiber and a second optical waveguide connected to the silicon waveguide, with a mode field diameter converter between them. The intermediary structure enables mode field diameter adjustment without modifying the silicon thin-wire waveguide itself, thus reducing connection loss while keeping the manufacturing process simple.
Solution Approach 2:
The patent divides the connection interface into separate functional segments: the single-mode optical fiber, the optical transformer (with its own waveguides and converter), and the silicon thin-wire waveguide. By segmenting the system, the mode field diameter adjustment function is isolated in the optical transformer module, allowing standard silicon thin-wire waveguides to be manufactured without special structures while still achieving low connection loss.
2Loss of energy
If a special structure is provided at the end of the silicon thin-wire waveguide to adjust the mode field diameter, then connection loss is reduced, but manufacturing yield deteriorates
Solution Approach 1:
The optical transformer serves as an intermediary that handles the mode field diameter conversion, eliminating the need to modify the silicon thin-wire waveguide structure. This allows standard, well-established manufacturing processes to be used for the silicon waveguides, maintaining high manufacturing yield while still achieving the required mode field matching through the separate optical transformer component.
3Loss of energy
If a special structure is provided at the end of the silicon thin-wire waveguide to adjust the mode field diameter, then connection loss is reduced, but cost increases
Solution Approach 1:
By segmenting the system into standard silicon thin-wire waveguides and separate optical transformer modules, the patent enables mass production of both components using established manufacturing techniques. The silicon waveguides can be fabricated using standard CMOS processes, while the optical transformers can be manufactured separately and integrated, avoiding the need for expensive, complex integrated structures and reducing overall manufacturing cost.
4Loss of energy
If silicon thin-wire waveguide and single-mode optical fiber are connected in multicore manner, then connection loss is reduced, but uniformity between ports deteriorates
Solution Approach 1:
The optical transformer is designed as a universal interface component that can handle multiple cores simultaneously while maintaining consistent performance. The standardized structure of the optical transformer with its mode field diameter converter provides uniform characteristics across all ports, enabling multicore connections with both low loss and high uniformity between ports.
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 reduces connection losses between the silicon thin-wire waveguide and single-mode optical fiber to 1 dB or less, simplifying manufacturing and maintaining high yield while optimizing the refractive-index differences in the planar lightwave circuit.
Implementation Method 1
a high relative refractive-index difference optical fiber 20... wherein the high relative refractive-index optical fiber is fusion-spliced at a first end surface thereof to the single-mode optical fiber
Implementation Method 2
a planar lightwave circuit including an optical waveguide having a second core formed of quartz-based glass doped with a refractive index raising dopant and a second cladding formed of quartz-based glass, thereby to guide light through the second core
Implementation Method 3
a silicon thin-wire waveguide element including a silicon thin-wire waveguide having a third core formed of silicon and a third cladding having a refractive index lower than the refractive index of the third core, thereby to guide light through the third core
Implementation Method 4
the high relative refractive-index optical fiber is fusion-spliced at a first end surface thereof to the single-mode optical fiber
Data Source
AI summary
An optical module includes a single-mode optical fiber; a high relative refractive-index difference optical fiber having a larger core-to-cladding relative refractive-index difference than that of the single-mode optical fiber fusion-spliced to a first end of the high relative refractive-index difference optical fiber; a planar lightwave circuit that includes an optical waveguide having a core of quartz-based glass doped with a refractive-index raising dopant and a cladding of quartz-based glass, and is connected at a first end thereof to a second end, opposite to the first end, of the high relative refractive-index difference optical fiber; and a silicon thin-wire waveguide element that includes a silicon thin-wire waveguide having a silicon core and a cladding whose refractive index lower than that of the silicon core, and is connected to a second end, opposite to the first end, of the optical waveguide of the planar lightwave circuit.