Optical Switch Absorption Modulation Without Phase Shift Tuning
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Solution Overview
Problem
Optical switch devices require precise tuning of phase shifts to achieve high contrast between on and off states, which complicates their design and increases the need for monitoring and high voltage sources.
Innovation Solution
The optical switch devices utilize modulation of absorption properties in optical waveguides to switch between states, eliminating the need for phase shift tuning and enabling compact, robust operation by varying carrier densities and absorption properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If phase shifters are used to achieve high speed optical switching, then switching speed is improved, but device complexity and manufacturing precision requirements increase due to the need for precise phase shift tuning
Solution Approach 1:
The patent extracts and eliminates the phase shifter component from the optical switch design. Instead of using phase shifters that require precise tuning, the invention uses direct absorption modulation through free carrier injection into the waveguide, thereby removing the source of complexity while maintaining high switching speed
Solution Approach 2:
The patent replaces the mechanical/electrical phase shifting mechanism with a direct optical absorption modulation mechanism. By injecting free carriers into the waveguide to change its absorption properties, the system substitutes complex phase control with simpler absorption-based switching
2Reliability
If phase shifters with high voltage sources are used, then switching contrast is improved, but the need for high voltage sources and monitoring increases device complexity
Solution Approach 1:
The patent implements self-service by using the injected free carriers to simultaneously achieve both the switching function and the absorption modulation. The same free carrier injection that enables switching also provides the absorption contrast, eliminating the need for separate high voltage sources and monitoring systems
Solution Approach 2:
The patent changes the operating parameter from phase shift control to absorption control. By modulating the absorption coefficient through free carrier injection rather than controlling phase shifts, the system achieves reliable switching contrast without requiring complex high voltage sources
3Volume of moving object
If absorption modulation is used instead of phase shift tuning, then device size is reduced, but manufacturing precision may be affected
Solution Approach 1:
The patent changes the fundamental operating parameter from phase to absorption, which inherently reduces device size since absorption modulation doesn't require the extended interaction lengths needed for phase shifting. The manufacturing precision is maintained through standard free carrier injection techniques
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 approach reduces the size of optical switch devices, eliminates the need for high voltage sources, and minimizes optical loss, providing efficient and stable switching operations.
Implementation Method 1
modulation of absorption properties in optical waveguides to switch between states, eliminating the need for phase shift tuning and enabling compact, robust operation by varying carrier densities and absorption properties
Data Source
AI summary
A method includes propagating light in a first waveguide of a 1×2 optical switch. The first waveguide is adjacent to a second waveguide in a coupling region. The 1×2 optical switch comprising an input to receive the light and couple the light to the first waveguide. The 1×2 optical switch further comprising a first output to output light from the first waveguide and a second output to output the light from the second waveguide. The method further includes coupling the light to the first output and the second output based on absorption values of the second waveguide in the coupling region; adjusting absorption values of the second waveguide in the coupling region such that light is directed from the input to only the first output; and coupling light to only the first output based on the adjusted absorption values of the second waveguide in the coupling region.