MxN WSS with Offset Fiber Array for Crosstalk Reduction
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Solution Overview
Problem
Conventional M×N wavelength selective switches (WSS) face challenges in achieving compressed port spacing without inducing crosstalk between signal paths, which affects their ability to maintain robust, error-free functionality and compact form factor.
Innovation Solution
The implementation of a laterally offset common port fiber array unit (FAU) and microlens array (MLA) configuration, which emits optical beams with angular or lateral offsets, reduces crosstalk by ensuring adjacent beams are laterally offset on the beam steering device, allowing for closer spacing of common port optical fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If port spacing is compressed to achieve compact form factor, then device size is reduced, but crosstalk between signal paths increases
Solution Approach 1:
The patent introduces a lateral offset dimension to the optical beam paths. By offsetting beams laterally in addition to angular separation, the system creates an extra spatial dimension for distinguishing adjacent signal paths. This allows ports to be spaced closer together while maintaining signal integrity, as the lateral offset provides additional separation between adjacent beams that would otherwise interfere with each other.
Solution Approach 2:
The patent employs asymmetric beam configurations where adjacent optical beams are assigned different lateral offsets. This asymmetric arrangement ensures that beams from different ports follow distinct spatial trajectories, preventing overlap and crosstalk even when ports are densely packed. The asymmetric lateral positioning complements the angular separation to provide robust crosstalk suppression.
2Object-generated harmful factors
If port spacing is increased to reduce crosstalk, then signal path separation is improved, but device size increases
Solution Approach 1:
Instead of relying solely on increased physical spacing between ports, the patent utilizes lateral offset as an additional spatial dimension. This allows the system to maintain small port spacing while achieving effective signal path separation through the combination of angular steering and lateral positioning, thus avoiding the need to increase device size.
Solution Approach 2:
The patent changes the spatial parameters of optical beams by introducing lateral offset as a controllable parameter. By adjusting the lateral offset parameter in conjunction with angular steering, the system achieves optimal signal separation without requiring increased physical distance between ports, thereby maintaining compact device dimensions while suppressing crosstalk.
3Object-generated harmful factors
If angular offset is increased to reduce crosstalk, then beam separation is improved, but beam steering complexity increases
Solution Approach 1:
The patent adds lateral offset as a second degree of freedom for beam separation, working in conjunction with angular offset. This two-dimensional separation approach (angular + lateral) allows for moderate angular offsets to be used while still achieving sufficient beam separation, thereby reducing the required angular steering range and simplifying the beam steering mechanism compared to relying solely on large angular offsets.
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 enables reduced crosstalk, allowing for more compact designs and increased port density while maintaining error-free functionality by ensuring that adjacent signal paths do not interfere with each other.
Implementation Method 1
a laterally offset one-dimensional MLA, or a laterally offset two-dimensional MLA
Implementation Method 2
a beam steering device configured to selectively direct angularly offset optical beams to add/drop port optical fibers
Implementation Method 3
one or more elements for selectively directing angularly offset optical beams
Data Source
AI summary
An M×N wavelength selective switch (WSS), may comprise a common port fiber array unit (FAU) configured to emit optical beams with a lateral offset and a beam steering device configured to direct optical beams with an angular offset to add/drop port optical fibers of an add/drop port FAU. The common port FAU may comprise a first set of common port optical fibers arranged in a first column of the common port FAU and a second set of common port optical fibers arranged in a second column of the common port FAU. The second column of the common port FAU may be laterally offset from the first column of the common port FAU. The beam steering device may be configured to selectively direct, in two dimensions, the optical beams with the angular offset to the add/drop port optical fibers.