Micro-ring Resonator Optical Switch for Bidirectional Add-Drop
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Solution Overview
Problem
Current optical switches for lower capacity networks, such as access and mobile backhaul, are costly and bulky, lacking the ability to efficiently add/drop or bypass optical signals of the same wavelength from opposite directions, which limits their application in these areas due to higher cost and footprint requirements.
Innovation Solution
A compact optical switch utilizing micro-ring resonators with active and inactive states, coupled between optical waveguides, allowing for bidirectional operation, add/drop, and bypass functions, along with optical modulation capabilities to support wavelength reuse and 'colourless' operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Wavelength selective devices (WSS) are used for optical switching, then optical switching capability is achieved, but cost and device footprint increase significantly
Solution Approach 1:
The patent replaces complex free-space optical WSS devices with integrated photonic circuits using micro-ring resonators. This substitution of mechanical/free-space optical systems with integrated photonic structures dramatically reduces device footprint and cost while maintaining optical switching functionality at lower capacities (10s to 100s Gbps).
Solution Approach 2:
The patent changes the operating parameters by using thermally tunable micro-ring resonators instead of complex WSS. By adjusting the thermal state of the micro-rings, the resonant wavelengths shift, enabling wavelength-selective switching. This parameter-based control simplifies the device structure and reduces footprint compared to mechanical WSS systems.
2Adaptability or versatility
If conventional optical add/drop multiplexers are used, then wavelength selection is achieved, but bidirectional operation and simultaneous add/drop of same wavelength from opposite directions is not possible
Solution Approach 1:
The patent implements bidirectional optical ports that can simultaneously perform add and drop functions for the same wavelength from opposite directions. Each port is designed to handle multiple functions (add, drop, bypass) in both directions, making the device universal and highly adaptable to different network configurations without requiring separate devices for each function.
Solution Approach 2:
The patent adds the spatial dimension of bidirectional operation to the wavelength-selective switching functionality. By designing optical ports that accept and process signals from both directions simultaneously, the device transitions from unidirectional to bidirectional operation, enabling simultaneous add/drop of same wavelength from opposite directions through the use of coupled micro-ring resonators that handle both directions independently.
3Use of energy by moving object
If optical switching is introduced in access and mobile backhaul networks, then energy saving and increased bandwidth are achieved, but cost and footprint requirements become critical barriers
Solution Approach 1:
The patent employs low-cost integrated photonic circuits with micro-ring resonators instead of expensive WSS devices. These integrated structures can be manufactured using standard semiconductor fabrication processes, making them economically viable for access and mobile backhaul networks where cost is critical. The devices are designed to be compact and potentially replaceable units that offer cost-effective optical switching.
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 low-cost, miniaturized optical switch enabling efficient optical switching in access and mobile backhaul networks with transparent and energy-efficient operation, supporting bidirectional signals and wavelength reuse, thus addressing the limitations of existing technologies.
Implementation Method 1
Each said switch element comprises a micro-ring resonator having an active state and an inactive state. In the active state, the micro-ring resonation is coupled to the first waveguide and to a respective one of the second and third waveguides for optical signals at a preselected wavelength.
Data Source
AI summary
An optical switch has four optical ports; a first optical waveguide coupled between a first of said ports and a second of the ports; a first switch element provided between the first waveguide and a second optical waveguide that is coupled to a third of the ports; a second switch element provided between the first waveguide and a third optical waveguide that is coupled to a fourth of the ports. Each switch element has a micro-ring resonator having an active state in which it is coupled to the first waveguide and to a respective one of the second and third waveguides for optical signals at a preselected wavelength, and an inactive state in which no coupling occurs. Each switch element has a control element arranged to receive a respective control signal configured to cause it to switch the micro-ring resonator between said states.