Wavelength Selective Switch Port Isolation via Angular Steering
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Solution Overview
Problem
Existing wavelength selective switches (WSS) with phased array switching engines face challenges in achieving high port isolation due to the overlap of unwanted diffraction orders, leading to inefficient use of the output optical aperture and complex calibration requirements.
Innovation Solution
A WSS configuration that directs selected diffraction orders within a concentrated angular region while steering all unwanted diffraction orders outside this region, thereby achieving increased port isolation without the need for complex calibration and control of the switching array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple diffraction orders are generated by the phased array switching engine, then wavelength channel routing flexibility is improved, but port isolation deteriorates due to overlap of unwanted diffraction orders
Solution Approach 1:
The patent segments the output optical aperture into distinct angular regions, assigning each region to specific diffraction orders. By spatially separating the angular ranges of different diffraction orders, the system prevents overlap of unwanted diffraction orders at output ports while maintaining routing flexibility through controlled steering of wanted orders.
Solution Approach 2:
The patent applies different angular steering characteristics to different diffraction orders. Each diffraction order is assigned a specific angular range within the output optical aperture, creating local quality differences in the angular distribution of different orders. This allows wanted diffraction orders to be steered to appropriate output ports while unwanted orders are directed to different angular regions that do not overlap.
2Area of stationary object
If output ports are closely spaced to increase density, then device compactness is improved, but port isolation deteriorates due to increased susceptibility to diffraction order overlap
Solution Approach 1:
The patent resolves the port spacing issue by transitioning from spatial separation in the physical domain to angular separation in the directional domain. Instead of increasing physical distance between closely spaced output ports, the system uses angular steering control to direct different diffraction orders into distinct angular regions, effectively separating them in the angular dimension while maintaining compact physical packaging.
3Object-affected harmful factors
If complex calibration and control techniques are applied to suppress unwanted diffraction orders, then port isolation is improved, but device complexity increases
Solution Approach 1:
The patent achieves port isolation by changing the angular parameter distribution of different diffraction orders. Instead of using complex calibration to suppress unwanted orders, the system modifies the angular steering parameters to naturally direct unwanted diffraction orders into distinct angular regions that do not overlap with wanted orders or adjacent output ports, simplifying the control requirements.
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 high port isolation by efficiently using the output optical aperture, preventing unwanted diffraction orders from reaching non-selected output ports, and maintaining a compact design without increasing physical size or design complexity.
Implementation Method 1
When each wavelength channel is diffracted or reflected by a phased array switching engine, multiple diffraction orders are generated and disperse at different angles from the switching engine.
Data Source
AI summary
By steering wanted diffraction orders within a concentrated angular region and steering all unwanted diffraction orders outside that region, a wavelength selective switch achieves high port isolation and densely spaced ports. N inputs receive an optical signal. Optics spatially separate and direct wavelength channels from the signal. A phased array switching engine comprising cells steers a wanted diffraction order of each spatially separated wavelength channel from each cell at an angle within a concentrated angular region relative to the PASE, and steers all unwanted diffraction orders of spatially separated wavelength channels from cells outside the concentrated angular region. Optics direct each wanted diffraction order to one of N outputs in accordance with the steering of the wanted diffraction orders by the PASE. The concentrated angular region is defined by a largest and smallest steering angle wherein the largest steering angle is a margin less than the smallest steering angle.