Co-axial Alignment Beam Optical Switch
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Solution Overview
Problem
There is a need for a low-cost and effective method for co-aligning optical beams, particularly for use in optical cross connect switches, as existing technologies are inefficient and require complex setups.
Innovation Solution
The system employs MEMS mirror arrays with vertical comb drive actuators and dichroic mirrors to align and switch optical fibers, using alignment beams and beam direction sensors for precise control, allowing for efficient reconfiguration of optical communication paths without converting signals to electrical form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex alignment methods are used to co-align optical beams, then alignment precision is improved, but device complexity increases and cost increases
Solution Approach 1:
The patent introduces alignment beams as intermediary optical elements that co-propagate with communication beams through the same optical path. These alignment beams serve as mediators to carry alignment information without interfering with communication signals, enabling precise beam alignment through intensity modulation detection rather than complex mechanical alignment systems
Solution Approach 2:
The patent replaces traditional mechanical alignment systems with an optical-based alignment method. Instead of using mechanical actuators and physical adjustment mechanisms to align beams, the system uses optical alignment beams whose intensity variations encode positional information, detected by photodetectors to guide alignment, thereby eliminating complex mechanical components
2Measurement precision
If traditional alignment methods are used, then alignment precision can be achieved, but recalibration frequency increases due to drift
Solution Approach 1:
The patent incorporates alignment beams into the optical path during the initial system setup and calibration phase. The alignment information is encoded into the communication beams themselves during normal operation, allowing the system to maintain alignment without frequent recalibration. The preliminary alignment configuration is preserved through the co-propagation mechanism
Solution Approach 2:
The system employs feedback through photodetectors that monitor the intensity of alignment beams. These detectors provide continuous alignment status information, allowing the system to detect and correct drift automatically. The feedback loop maintains alignment precision over time without requiring manual recalibration intervention
3Ease of operation
If optical signals are converted to electrical signals for switching, then switching control is improved, but signal loss increases and system complexity increases
Solution Approach 1:
The patent replaces electrical-optical conversion switching with all-optical switching using MEMS mirrors. The mirrors physically redirect optical beams based on control signals without converting the optical signal to electrical form. This maintains signal integrity and eliminates conversion losses while achieving precise switching control through mechanical mirror positioning
Solution Approach 2:
The MEMS mirror array serves multiple functions: it acts as both the switching element and the beam steering mechanism. The same optical path carries both communication signals and alignment beams, and the same mirrors control both functions, reducing the need for separate electrical control pathways and signal conversion components
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 solution enables efficient and low-cost co-alignment of optical beams, reducing drift and requiring minimal recalibration, while allowing for rapid reconfiguration of optical paths, enhancing the performance and reliability of optical cross connect switches.
Implementation Method 1
A source of infrared light, such as a vertical cavity surface emitting laser (VCSEL)
Implementation Method 2
Each communication beam is reflected from a dichroic mirror that also is responsive to the wavelength of the communication beam
Implementation Method 3
The control system includes a beam direction sensor unit that detects the co-aligned alignment beams
Implementation Method 4
The optical switch elements are mirrors in a micromechanical mirror array that are individually positionable by application of voltages to the mirror array
Data Source
AI summary
A method and system for creating and co-aligning a first array of optical beams with a second array of optical beams. In a preferred application the invention is used in a cross connect optical switch. A first set of alignment beams are created and added to and aligned co-axially with each of the first set of parallel collimated cross-connect communication beams. A second set of alignment beams are created and added to and aligned co-axially with each of the second set of parallel collimated cross-connect communication beams. A preferred embodiment includes an injection unit with a “point” infrared light source such as a vertical cavity surface emitting laser (VCSEL) operating in the near infrared at 850 nm and having a divergence of about 30 degrees. The beam from this source is collimated with collimator optics to produce a collimated beam with a cross sectional dimension of about 16 millimeter×16 millimeters. This collimated beam is separated into 128 separate beams with a mask having 128 0.6 mm diameter apertures that are positioned to align the 128 separate parallel beams with the communication beams from a fiber bundle.