Optical Arrangement Suppressing Outerband Crosstalk in Wavelength Selective Switches
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Solution Overview
Problem
Wavelength selective switches in optical communication networks face issues of undesirable optical coupling between input and output ports and outerband crosstalk, which affect the performance and efficiency of the network.
Innovation Solution
An optical device with a programmable optical phase modulator and polarizing arrangement that spatially separates optical beams into different polarization states, allowing selective coupling and preventing coupling between certain ports, while using polarizers to suppress outerband crosstalk by arranging optical energy into orthogonal polarization states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wavelength selective switch is used for reconfigurable wavelength-dependent switching, then service deployment is accelerated and network rerouting capability is improved, but outerband crosstalk and undesirable optical coupling between ports occur
Solution Approach 1:
A polarizing arrangement is introduced as an intermediary element in the optical path between the optical ports and the programmable optical phase modulator. This polarizing arrangement converts optical energy from the optical ports into a polarization state orthogonal to the first polarization state used by the modulator, thereby suppressing outerband crosstalk that would otherwise be generated by reflections from the non-active area of the modulator.
2Adaptability or versatility
If wavelength selective switch is used for reconfigurable wavelength-dependent switching, then network rerouting capability is improved, but undesirable optical coupling between input and output ports occurs
Solution Approach 1:
The polarizing arrangement acts as a mediator that selectively allows optical energy to pass through to the programmable optical phase modulator only when it is in the correct polarization state. Optical energy reflected from the non-active area that maintains the original polarization state is blocked, preventing undesirable optical coupling between different input and output ports while maintaining the desired rerouting capability.
3Reliability
If polarizing arrangement is added to suppress outerband crosstalk, then outerband crosstalk is reduced and port isolation is improved, but device complexity increases
Solution Approach 1:
The solution changes the polarization state parameter of the optical energy as it passes through the system. By using a polarizing arrangement to convert optical energy into an orthogonal polarization state, the system achieves improved port isolation and reduced outerband crosstalk. This parameter change approach adds minimal complexity compared to other potential solutions while effectively addressing the crosstalk issue.
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 achieves reduced optical coupling between ports, improved isolation, and suppression of outerband crosstalk, enhancing the directional coupling and efficiency of optical switches in wavelength selective switches.
Implementation Method 1
An optical arrangement arranges an optical beam received from any of the optical ports into a first polarization state
Implementation Method 2
A dispersion element spatially separates the optical beam into a plurality of wavelength components
Implementation Method 3
A programmable optical phase modulator receives the focused plurality of wavelength components in the first polarization state
Implementation Method 4
A polarizing arrangement is located in an optical path between at least one of the optical ports and at least a portion of the non-active area of the programmable optical phase modulator. The polarizing arrangement is configured to arrange optical energy into a second polarization state orthogonal to the first polarization state
Data Source
AI summary
An optical device includes at least three optical ports. An optical arrangement arranges an optical beam received from any of the optical ports into a first polarization state. A dispersion element spatially separates the optical beam into a plurality of wavelength components. An optical power element converges each wavelength component in at least one direction. A programmable optical phase modulator steers the wavelength components through the optical arrangement, the dispersion element and the focusing element to a selected optical output. The programmable optical phase modulator includes an active area that performs the steering and a non-active area surrounding the active area. A polarizing arrangement located in an optical path between at least one of the optical ports and at least a portion of the non-active area of the programmable optical phase modulator is configured to arrange optical energy into a second polarization state orthogonal to the first polarization state.