Micro-ring Resonator Optical Switch for Compact WDM Networks
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Solution Overview
Problem
Wavelength selective optical switches used in WDM optical networks are costly and bulky, making them unsuitable for radio access networks, and existing alternatives like FOADMs lack reconfigurability for fault protection.
Innovation Solution
An optical switch utilizing a micro-ring resonator to add or drop optical signals in either direction through a single optical waveguide, enabling cost-effective, power-efficient, and compact switching with reconfigurable protection mechanisms, implemented in a silicon photonic device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wavelength selective switches (WSSs) based on free space optics are used in WDM optical networks, then wavelength selective switching capability is achieved, but the device becomes costly and bulky
Solution Approach 1:
The patent replaces free space optical mechanisms with integrated photonic waveguide structures. The micro-ring resonator is formed within a planar lightwave circuit substrate, eliminating the need for bulk optical components and free space propagation paths. This substitution of mechanical/free-space optics with integrated photonic circuits directly reduces device size and complexity while maintaining wavelength selective switching functionality.
Solution Approach 2:
The patent changes the operational parameters by using evanescent field coupling between the micro-ring resonator and waveguides instead of free space optical coupling. This parameter change enables compact integration while achieving the same wavelength selective effect, thereby reducing device size and manufacturing cost.
2Device complexity
If fixed optical add drop multiplexers (FOADMs) comprising thin film filters are used, then device simplicity is achieved, but reconfigurability for fault protection is lost
Solution Approach 1:
The patent introduces dynamic control capability by making the micro-ring resonator reconfigurable. Through thermal, electro-optic, or other actuation mechanisms, the resonance condition of the micro-ring can be dynamically adjusted, enabling the device to switch between different wavelengths or operational states. This dynamic property provides fault protection and adaptability while maintaining the simplicity of the integrated photonic structure.
Solution Approach 2:
The integrated photonic switch with micro-ring resonator serves multiple functions: wavelength selective add/drop, routing, and fault protection. The same compact structure that provides wavelength selectivity also enables reconfigurability for protection switching, eliminating the need for separate dedicated protection mechanisms and enhancing versatility.
3Ease of manufacture
If conventional WSSs are used in radio access networks, then wavelength selective switching is achieved, but high cost and large size prohibit adoption
Solution Approach 1:
The patent merges wavelength selective switching functionality with fault protection capability into a single integrated photonic device. The micro-ring resonator-based switch can perform both normal wavelength routing and protection switching functions, eliminating the need for separate protection equipment and reducing overall system cost while improving reliability.
Solution Approach 2:
By replacing conventional free space optics with integrated photonic circuits, the patent achieves both cost reduction and improved reliability. The integrated structure is more robust, smaller in size, and can be mass-produced using semiconductor fabrication techniques, making it suitable for widespread deployment in radio access networks while maintaining fault protection capabilities.
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
The solution provides a cheaper, more reliable, and less bulky optical switch with integrated protection capabilities, allowing for efficient wavelength management and fault tolerance in optical communications networks, particularly in radio access networks.
Implementation Method 1
a micro-ring resonator. The micro-ring resonator is operable to add a first optical signal at a preselected wavelength received from a first optical add path to a first optical waveguide
Implementation Method 2
The micro-ring resonator is operable to drop a first optical signal at a preselected wavelength travelling in a first direction through a first optical waveguide to a first optical drop path
Data Source
Figure 1
Figure 2a~3a
Figure 2b~3b
AI summary
An optical switch, comprising: a first optical waveguide, a first optical add path, a second optical add path and a micro-ring resonator. The micro-ring resonator is operable to add a first optical signal at a preselected wavelength received from the first optical add path to the first optical waveguide to travel in a first direction through the first optical waveguide. The micro-ring resonator is further operable to add a second optical signal at the preselected wavelength received from the second optical add path to the first optical waveguide to travel in a second direction through the first optical waveguide opposite to the first direction. There is also provided an optical drop switch, an optical switching apparatus, an optical communications network node and an optical communications network.