MEMS Optical Switch Module with Alignment Beams
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Solution Overview
Problem
There is a need for large-scale, reliable optical switches that can quickly and efficiently route optical signals between arrays of input and output fibers with minimal power loss and at a minimal cost per channel, particularly in growing telecommunications systems.
Innovation Solution
An all-optical cross-connect switch utilizing MEMS mirrors for cross-connecting optical fibers, with two MEMS mirror arrays driven in two axes by vertical comb drive actuators, and a MEMS control system for precise alignment and beam direction, allowing for rapid reconfiguration of optical paths with minimal power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hybrid optical-electrical-optical switches are used for detection and conversion of optical signals, then switching speed and reliability are improved, but device complexity and power loss increase
Solution Approach 1:
The patent replaces the hybrid optical-electrical-optical switching mechanism with a pure optical switching mechanism using MEMS mirrors. The MEMS mirrors directly deflect optical beams between input and output fibers without electrical signal conversion, eliminating the complexity of photodetectors, electrical signal processing circuits, and optical transmitters while maintaining switching reliability through precise mechanical mirror positioning controlled by simple comb drive actuators.
2Measurement precision
If MEMS mirrors with tight tolerances are used for angular alignment, then beam direction precision is improved, but manufacturing difficulty and cost increase
Solution Approach 1:
The patent divides the beam direction control into two independent stages: coarse positioning handled by the MEMS mirror array with tight tolerances, and fine positioning handled by the fiber array with adjustable spacing. This segmentation allows each subsystem to be optimized independently - the MEMS mirrors focus on angular alignment precision while the fiber array compensates for positioning variations, thereby reducing overall manufacturing difficulty.
Solution Approach 2:
The patent introduces an intermediary alignment beam system that projects reference beams through the MEMS mirrors to verify and adjust beam paths. This intermediary alignment mechanism serves as a mediator between the MEMS mirror positioning and the final beam direction, allowing for precise calibration without requiring extremely tight manufacturing tolerances on the MEMS mirrors themselves.
3Measurement precision
If sophisticated feedback control systems are implemented for MEMS mirror alignment, then alignment accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements a self-aligning mechanism where the system automatically establishes proper beam paths through the interaction of alignment beams with the MEMS mirrors and fiber arrays. The alignment beams project through the system and the physical interaction of light with the optical components creates natural feedback that guides the system to the correct configuration without requiring complex external control systems.
Solution Approach 2:
The patent pre-configures the fiber arrays with specific spacing and positioning arrangements that are designed to work in conjunction with the MEMS mirror deflection ranges. The fiber arrays are preliminarily positioned to receive beams from the MEMS mirrors at the expected angles, eliminating the need for complex real-time feedback control during operation. The system is pre-set to achieve proper alignment through its physical geometry.
4Productivity
If fiber routes are reconfigured to reduce crowdedness, then system efficiency is improved, but switching time and operational complexity increase
Solution Approach 1:
The patent implements a dynamic switching system using MEMS mirrors that can rapidly change beam directions by adjusting mirror angles. The mirrors are driven by comb drive actuators that can quickly reposition the mirrors to deflect beams to different output fibers. This dynamic capability allows the system to reconfigure fiber routes in real-time to balance traffic loads and reduce crowdedness on specific fibers, improving overall system efficiency without significant switching delays.
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 enables rapid, reliable, and efficient switching of optical signals between fiber arrays with minimal power loss and cost, suitable for large-scale telecommunications systems, maintaining high accuracy and adaptability to environmental changes.
Implementation Method 1
Each of the mirrors is positioned and angled by comb drive actuators operated with voltages applied through integrated circuits
Implementation Method 2
Two MEMS mirror arrays reflect communication beams from fibers in a first array to fibers in a second array
Implementation Method 3
A dichroic mirror reflects the communication beams and transmits the alignment beams
Data Source
Figure 1
Figure 1A~1B
Figure 2A~2B
AI summary
The present invention provides an all optical cross connect switch utilizing two-axis MEMS mirrors for cross connecting optical fibers in a first set of optical fibers to optical fibers in a second set of optical fibers. The optical fibers in the first and second sets of optical fibers are precisely positioned in a first fiber-microlens positioning array to define a first set of parallel collimated cross-connect communication beam paths, with each collimated cross-connect communication beam path connecting an optical fiber in the first set of optical fibers with a MEMS mirror in a first MEMS mirror array. Alignment beams are added to and aligned co- axially with each of the first and second sets of parallel collimated cross-connect communication beams. Two beam direction sensor units are positioned to detect each alignment beam in the first and second sets of alignment beams transmitted through the dichroic mirror and a MEMS control system controls the positions of the MEMS mirrors to connect optical fibers in the first set of optical fibers to any of the optical fibers in the second set of optical fibers.