LCoS Wavelength Selective Switch With Wavefront Control for Isolation
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Solution Overview
Problem
Conventional wavelength selective switches (WSS) face increased crosstalk due to the expansion of port quantity, which is caused by the increase in maximum beam deflection angle, leading to decreased diffraction efficiency and isolation.
Innovation Solution
The integration of a wavefront control element with the LCoS in the WSS, which modulates optical signals to suppress diffraction sub-peaks and improve isolation, reducing crosstalk by jointly modulating the optical signals with the LCoS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the maximum beam deflection angle is increased to support port quantity expansion, then the port quantity of the WSS is increased, but the diffraction efficiency and isolation of deflected beams are decreased, leading to increased crosstalk
Solution Approach 1:
A wavefront control element is introduced as an intermediary component between the incident beam and the LCoS. This wavefront control element pre-modulates the optical wavefront to compensate for the increased beam deflection angle, thereby maintaining high diffraction efficiency and isolation even when the maximum beam deflection angle is increased for port expansion.
Solution Approach 2:
The patent changes the wavefront parameters of the incident beam by introducing a wavefront control element that adjusts the wavefront shape and phase distribution. This parameter modification allows the system to maintain optimal diffraction characteristics at larger beam deflection angles, resolving the contradiction between port expansion and isolation performance.
2Adaptability or versatility
If the maximum beam deflection angle is increased to support port quantity expansion, then the port quantity of the WSS is increased, but the diffraction efficiency of the LCoS is decreased, leading to increased crosstalk
Solution Approach 1:
The wavefront control element serves as a mediator that optimizes the wavefront characteristics before the beam reaches the LCoS. This pre-conditioning of the wavefront ensures that even at large deflection angles, the LCoS operates at peak diffraction efficiency, preventing energy loss while supporting expanded port capacity.
Solution Approach 2:
The wavefront control element performs preliminary wavefront modulation before the optical signal interacts with the LCoS. This preliminary action prepares the wavefront in advance to withstand the high deflection angles required for port expansion, ensuring diffraction efficiency is maintained without energy loss.
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 effectively suppresses diffraction sub-peaks, enhancing the isolation and significantly reducing crosstalk in the WSS, thereby improving the performance of optical networks.
Implementation Method 1
The LCoS is a reflective diffraction grating programmable to realize a specific phase distribution, whose main function is to deflect an incident beam to a corresponding emergent direction
Implementation Method 2
a wavefront control element, having N*M array elements... Each of the N*M array elements modulates a corresponding optical signal in the N*M optical signals received by the input port fiber array, so that the WSS suppresses a diffraction sub-peak generated when the corresponding optical signal passes through the LCoS
Implementation Method 3
The LCoS is a reflective diffraction grating programmable to realize a specific phase distribution, whose main function is to deflect an incident beam to a corresponding emergent direction
Implementation Method 4
The LCoS is a reflective diffraction grating programmable to realize a specific phase distribution
Implementation Method 5
demultiplexing/multiplexing gratings 102 and 105
Data Source
Figure 1A~2
Figure 3A
Figure 3B~4
AI summary
A WSS (200) is provided, which may be used in a backbone network, a metropolitan area network, and a data center. The WSS (200) includes an input port fiber array (201, 301, 501, 701, 901), a demultiplexing/multiplexing grating group (202), an output port fiber array (203, 305, 306, 506, 706, 906), and a beam deflection component group (204) including two beam deflection components and at least one wavefront control element (306, 307, 308, 309, 507, 508, 707, 708). At least one beam deflection component is a liquid crystal on silicon LCoS (303, 304, 503, 504, 703, 704). The wavefront control element (306, 307, 308, 309, 507, 508, 707, 708) is located on an optical path between the demultiplexing/multiplexing grating group (202) and the beam deflection component group (204), or integrated with the LCoS (303, 304, 503, 504, 703, 704). The input port fiber array (201, 301, 501, 701, 901) includes N ports, configured to receive multi-wavelength optical signals. The demultiplexing/multiplexing grating group (202) demultiplexes and outputs the multi-wavelength optical signals. The beam deflection component group (204) deflects the multi-wavelength optical signals to the demultiplexing/multiplexing grating group (202). The demultiplexing/multiplexing grating group (202) multiplexes the multi-wavelength optical signals to the output port fiber array (203, 305, 306, 506, 706, 906). The wavefront control element (306, 307, 308, 309, 507, 508, 707, 708) and the LCoS (303, 304, 503, 504, 703, 704) jointly modulate optical signals transmitted through N∗M wavelength channels, to suppress diffraction sub-peaks generated when the optical signals pass through the LCoS (303, 304, 503, 504, 703, 704). In this way, diffraction sub-peaks of deflected beams are suppressed, and isolation is improved.