SLM-Based ROADM Using Integral Bragg Grating
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Solution Overview
Problem
Current ROADM architectures lack fault tolerance and require bulk retro-reflection optical elements, which increase cost, complexity, and size, and do not allow for compact form-factors essential in fiber-optics applications.
Innovation Solution
A spatial light modulator (SLM) with an integral, lateral-gradient volume Bragg grating is used to route optical channels without the need for bulk retro-reflection elements, enabling a compact and fault-tolerant ROADM that can switch multiple wavelengths and maintain reversibility in both bar and cross states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If bulk retro-reflection optical elements are used in ROADM, then wavelength routing functionality is achieved, but device complexity and size increase
Solution Approach 1:
The patent extracts and eliminates the bulk retro-reflection optical elements from the ROADM architecture. By removing these separate components, the invention integrates the retro-reflection function directly into the SLM device, thereby reducing device complexity and size while maintaining the wavelength routing functionality and improving fault tolerance through a more compact, integrated structure.
Solution Approach 2:
The patent merges the retro-reflection function with the SLM device by integrating a reflective grating structure directly onto the SLM surface. This combination eliminates the need for separate bulk retro-reflection elements, reducing the overall device complexity and size while maintaining full wavelength routing capability and improving system reliability.
2Device complexity
If bulk retro-reflection optical elements are used in ROADM, then wavelength routing is enabled, but cost increases
Solution Approach 1:
The patent extracts the bulk retro-reflection optical elements from the system and replaces them with an integrated reflective grating on the SLM. This elimination of separate components reduces manufacturing costs by reducing the number of parts that need to be procured, aligned, and assembled, while maintaining the wavelength routing functionality.
Solution Approach 2:
The patent combines the retro-reflection function with the SLM device through integration of a reflective grating structure. This merging eliminates the need for separate bulk optical elements, thereby reducing component count, simplifying assembly procedures, and lowering overall manufacturing costs while maintaining full routing capability.
3Device complexity
If bulk retro-reflection optical elements are used in ROADM, then optical channel routing is achieved, but device size increases
Solution Approach 1:
The patent extracts and removes the bulky retro-reflection optical elements from the ROADM architecture. By eliminating these separate components and integrating the retro-reflection function into the SLM, the device achieves a compact form factor suitable for fiber-optics applications while maintaining wavelength routing functionality.
Solution Approach 2:
The patent merges the retro-reflection function with the SLM device through direct integration of a reflective grating structure on the SLM surface. This integration eliminates the need for separate bulk optical elements, dramatically reducing the overall device size and enabling a compact ROADM design.
4Volume of moving object
If SLM with integral Bragg grating is used, then compactness is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent replaces traditional mechanical alignment and assembly processes with direct fabrication of the Bragg grating structure on the SLM surface. This substitution of mechanical systems with integrated optical fabrication techniques enables compact device design while managing manufacturing precision requirements through direct writing or lithography methods.
Solution Approach 2:
The patent utilizes changes in the physical and chemical parameters of the SLM surface during grating fabrication to achieve the desired compact design. By controlling parameters such as grating period, depth, and orientation during the fabrication process, the invention achieves compactness while managing manufacturing precision through parameter optimization rather than mechanical adjustment.
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 SLM-based ROADM achieves compactness, fault tolerance, and efficient wavelength routing, reducing light losses and operational complexity while maintaining reversibility, thus addressing the limitations of existing architectures.
Implementation Method 1
A spatial light modulator (SLM) with an integral, lateral-gradient volume Bragg grating is used to route optical channels
Implementation Method 2
The SLM acts as a blazed grating configured to produce a diffracted light beam in a Littrow configuration
Data Source
AI summary
A reconfigurable optical add-drop multiplexer (ROADM) and a method of passing at least one optical channel through the multiplexer. In one embodiment, the multiplexer includes: (1) a main input port, (2) a main output port, (3) an add input port, (4) a drop output port, (5) dispersive optics configured spatially to spread and recombine optical spectra containing optical channels and (6) a spatial light modulator having an integral, lateral-gradient volume Bragg grating and configured to assume a bar state in which at least one of the optical channels is passed from the main input port to the main output port and at least another of the optical channels is passed from the add input port to the drop output port and a cross state in which the integral, lateral-gradient volume Bragg grating is transmissive with respect to the channels.