Wavelength Selective Switch with Position Control for Crosstalk Reduction
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Solution Overview
Problem
Wavelength selective switches face challenges in handling broadband wavelength ranges due to spatial separation limitations, leading to increased crosstalk, as they are typically designed to operate within the C-band and struggle to effectively manage broader wavelength ranges.
Innovation Solution
A wavelength selective switch is designed with an optical input port, a wavelength dispersion unit that spatially separates light by varying emission angles, and a deflection unit that adjusts reflection or transmission angles, incorporating a wavelength dispersive element like a liquid crystal diffraction element with a position control mechanism to change the position or angle of the dispersive element, enabling operation across multiple wavelength bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single wavelength selective switch is used to cover all wavelength bands, then the device complexity is reduced, but the spatial separation becomes insufficient and crosstalk deteriorates
Solution Approach 1:
The wavelength selective switch is divided into multiple independent WSS units, each responsible for a specific wavelength band (e.g., C-band, L-band, S-band). Each WSS unit contains its own wavelength dispersive element and spatial modulator, enabling independent optimization for each band while maintaining low crosstalk performance.
Solution Approach 2:
The wavelength selective switch is designed with a common control unit that manages multiple WSS units, and a common output unit that aggregates signals from all bands. This multi-functional architecture allows a single device to handle multiple wavelength bands simultaneously while maintaining the performance benefits of segmented processing.
2Reliability
If the physical size of the spatial modulator is increased to improve spatial separation, then crosstalk is reduced, but the device becomes impractically large
Solution Approach 1:
By segmenting the wavelength spectrum into multiple bands and assigning each band to a separate WSS unit with its own spatial modulator, each modulator only needs to handle a portion of the total wavelength range. This allows the use of compact spatial modulators with sufficient spatial separation for their respective bands, avoiding the need for an excessively large single modulator.
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 allows the wavelength selective switch to effectively handle broadband wavelength ranges with reduced crosstalk, enabling efficient separation and distribution of wavelength components across various bands, thereby improving communication speed and reliability.
Implementation Method 1
a wavelength dispersion unit that spatially separates light incident from the optical input port for each of wavelengths and emits the separated light such that an emission angle of the incident light varies for each of predetermined wavelength ranges
Implementation Method 2
the wavelength dispersive element includes a liquid crystal diffraction element
Implementation Method 3
a deflection unit that couples light incident from the wavelength dispersion unit to the optical output port by deflecting the incident light such that a reflection angle or a transmission angle of the incident light is variable for each of wavelengths
Data Source
AI summary
Provided are a wavelength selective switch capable of dealing with a broadband wavelength range with reduced crosstalk and an optical cross-connect device including the wavelength selective switch. The wavelength selective switch includes an optical input port; an optical output port; a wavelength dispersion unit that spatially separates light incident from the optical input port for each of wavelengths and emits the separated light such that an emission angle of the incident light varies for each of predetermined wavelength ranges; and a deflection unit that couples light incident from the wavelength dispersion unit to the optical output port by deflecting the incident light such that a reflection angle or a transmission angle of the incident light is variable for each of wavelengths, in which the wavelength dispersion unit includes a wavelength dispersive element and a position control mechanism that reversibly changes a position or an angle of the wavelength dispersive element or both the position and the angle with respect to the optical input port.