Reconfigurable Optical Add-Drop Multiplexer With Low Power Phase Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated-optics-based switching systems face challenges in achieving low power consumption and broad-band operation due to high power requirements of heater elements and narrow filter bandwidths of ring resonator elements, which limit their utility in large-port-count and broadband applications.
Innovation Solution
The use of frequency-filter blocks with cascaded tunable Mach-Zehnder Interferometer (MZI) elements and tunable couplers, along with low-power-dissipation stress-optic or liquid-crystal phase controllers, enables a flat-top frequency response and independent control of wavelength propagation, reducing power consumption and enhancing broadband capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If heater elements are used in integrated-optics-based switching systems, then phase control and wavelength routing are achieved, but power consumption increases significantly
Solution Approach 1:
The patent replaces thermal/thermal-optic phase control mechanisms with electro-optic phase control using the Pockels effect. This substitution eliminates the need for high-power heater elements and enables low-power consumption operation while maintaining full phase control capability for wavelength routing.
Solution Approach 2:
The patent changes the physical mechanism from thermal heating to electro-optic modulation. By applying voltage to induce the Pockles effect in electro-optic materials, the refractive index is modulated directly without thermal conversion, achieving phase control with minimal power consumption.
2Adaptability or versatility
If ring resonator elements are used, then wavelength filtering is achieved, but filter bandwidth is narrow limiting broadband operation
Solution Approach 1:
The patent segments the wavelength filtering function into multiple independent MZI-based filter blocks. Each MZI can be independently tuned to provide broad bandwidth, and multiple blocks work in cascade to achieve both broadband operation and selective wavelength filtering, overcoming the narrow bandwidth limitation of ring resonators.
Solution Approach 2:
The patent employs dynamically tunable MZI elements with electro-optic phase control, allowing real-time adjustment of filter characteristics. This dynamic capability enables broad operational bandwidth and flexible wavelength selection, contrasting with the fixed narrow bandwidth of ring resonators.
3Ease of operation
If free-space MEMS mirror arrays or LCOS are used for optical switching, then wavelength routing is achieved, but system size and complexity increase
Solution Approach 1:
The patent replaces free-space mechanical switching systems (MEMS mirrors, LCOS) with integrated photonic circuit implementations. This substitution eliminates the need for free-space optical paths, mechanical moving parts, and complex alignment mechanisms, achieving wavelength routing through compact integrated waveguide structures with electro-optic control.
Solution Approach 2:
The patent implements a nested hierarchical structure where multiple MZI elements are cascaded within filter blocks, which are in turn cascaded within the overall optical switch architecture. This nested arrangement enables complex wavelength routing functionality to be achieved through simple, compact integrated components rather than large free-space systems.
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 solution allows for efficient, low-power optical switching systems suitable for broadband communications, achieving substantial power savings and improved performance in large-scale systems like ROADM and OXC, with minimal optical loss and flat-top responses across a wide spectral range.
Implementation Method 1
low-power-dissipation stress-optic phase controllers
Implementation Method 2
low-power-dissipation stress-optic or liquid-crystal phase controllers
Implementation Method 3
cascaded tunable Mach-Zehnder Interferometer (MZI) elements
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
An approach for realizing low-power, high-port-count optical switching systems, such as OXCs, WXCs, and ROADMs is presented. Optical switching systems in accordance with the present disclosure include arrangements of frequency-filter blocks, each of which includes a cascaded arrangement of tunable couplers and tunable Mach-Zehnder Interferometers (MZIs) that provides a substantially flat-top broadband transfer function for the frequency-filter block. The tunability for these devices is achieved by operatively coupling a low-power-dissipation phase controller, such as a stress-optic phase controller or liquid-crystal-based phase controller with one arm of the device, thereby enabling control over the coupling coefficient of the device.