LCOS Blazed Grating Crosstalk Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical power equilibrium solutions based on LCOS fail to reduce crosstalk signal power, leading to unsatisfactory crosstalk features in optical cross devices, particularly in wavelength selective switches (WSS) used in reconfigurable optical add/drop multiplexers (ROADM), which affects network management and signal quality.
Innovation Solution
Configuring the LCOS as a blazed grating pattern with periodically changing phase, where each period has three grating segments, and reducing the phase modulation depth and pixel quantity of the second grating segment if the wavelength signal power exceeds the target, to achieve power equilibrium and minimize crosstalk signal power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If phase modulation depth and pixel quantity of the second grating segment are reduced, then crosstalk signal power is reduced, but the complexity of controlling the LCOS increases
Solution Approach 1:
The LCOS is divided into multiple grating segments (first, second, and third grating segments) within each period. By segmenting the grating structure, the patent can independently control the phase modulation depth and pixel quantity of the second grating segment to reduce crosstalk signal power while maintaining the overall blazed grating pattern for wavelength signal processing.
Solution Approach 2:
The patent applies different phase modulation depths and pixel quantities to different grating segments. Specifically, the second grating segment has reduced phase modulation depth and pixel quantity to minimize crosstalk, while the first and third grating segments maintain their original characteristics for proper wavelength signal diffraction. This local differentiation allows targeted crosstalk reduction without compromising overall system function.
2Object-generated harmful factors
If additional hardware is added to reduce crosstalk, then crosstalk feature meets system requirements, but device complexity and cost increase
Solution Approach 1:
The LCOS device performs dual functions: it maintains its primary role in wavelength signal diffraction while simultaneously reducing crosstalk signal power through its segmented grating structure. The same LCOS device that directs wavelength signals also generates the reduced crosstalk effect, eliminating the need for separate crosstalk suppression hardware.
Solution Approach 2:
The segmented blazed grating pattern on the LCOS serves multiple purposes: it maintains wavelength signal routing functionality while simultaneously suppressing crosstalk signals. This multi-functionality is achieved by configuring the second grating segment with specific phase modulation and pixel quantity parameters that address both signal processing and crosstalk reduction in a single device.
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 method effectively reduces crosstalk signal power, ensuring that the crosstalk feature meets system requirements without additional hardware, thereby improving port isolation and maintaining signal quality in optical cross devices.
Implementation Method 1
configuring the LCOS as a blazed grating pattern whose phase periodically changes
Implementation Method 2
configuring the LCOS as a blazed grating pattern
Implementation Method 3
reducing a phase modulation depth and a pixel quantity of the second grating segment
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The present invention discloses an optical power equilibrium method and apparatus. The method includes: configuring a liquid crystal on silicon LCOS as a blazed grating pattern whose phase periodically changes, where each period includes three grating segments, a pixel quantity in each period does not change, and a second grating segment is located between a first grating segment and a third grating segment; monitoring power of wavelength signals in a WDM signal, where the WDM signal includes a first wavelength signal; and reducing a phase modulation depth and a pixel quantity of the second grating segment in each period at a first location if power of the first wavelength signal is greater than preset target power, so that the power of the first wavelength signal is the same as the target power, where the first location is a location at which the first wavelength signal is incident to the LCOS. The method and apparatus provided in the present invention resolve a problem that in the prior art, power of crosstalk signals generated in an LCOS by wavelength signals is not reduced, and a crosstalk feature of a port cannot satisfy a system requirement.