Laser-Induced Plasma Filament for Free-Space Optical Communication
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Solution Overview
Problem
Free-space laser communication systems experience performance degradation due to adverse conditions such as heavy fog or smoke, which obscure the line of sight and cause high-loss conditions, leading to bit error rate degradation and system failure.
Innovation Solution
The system employs a first laser to generate a laser-induced plasma filament within an optically-transparent medium, using high-power, ultra-short pulses, which acts as a low-loss conduit for a communication laser beam, allowing it to propagate through adverse conditions like fog and clouds, and includes a signal combiner to direct the communication signal through the filament to the receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional laser beam is used for free-space optical communication, then the system is simple to operate, but the signal experiences high loss and performance degradation in adverse conditions such as heavy fog or smoke
Solution Approach 1:
The patent applies preliminary action by generating the plasma filament in advance before the communication laser beam is transmitted. The first laser creates the plasma filament structure ahead of time, which then serves as a low-loss conduit for the subsequent communication signal, thereby improving reliability without requiring real-time adaptation during signal transmission
Solution Approach 2:
The patent introduces plasma filament as an intermediary medium between the transmitter and receiver. This plasma filament acts as a mediator that guides and protects the communication laser beam through adverse atmospheric conditions, reducing signal loss and improving transmission reliability while maintaining relatively simple system operation
2Productivity
If high-power ultra-short pulses are used to generate plasma filament, then communication range and bit rate are extended, but energy consumption increases
Solution Approach 1:
The patent employs periodic action by using pulsed laser operation rather than continuous wave. The first laser emits high-power ultra-short pulses at specific intervals to generate and maintain the plasma filament, which reduces average energy consumption compared to continuous operation while still achieving extended communication range and high bit rates during the pulse intervals
Solution Approach 2:
The patent applies parameter changes by utilizing ultra-short pulse duration and high peak power parameters. This allows the system to achieve the necessary plasma filament generation with reduced total energy input, as the high power is concentrated in extremely short time intervals, thereby improving productivity without proportionally increasing energy consumption
3Loss of energy
If plasma filament is generated to guide communication beam through adverse conditions, then signal loss is reduced, but the system becomes more complex with additional lasers and signal combiners
Solution Approach 1:
The patent applies merging by combining the first laser (for plasma filament generation) and the second laser (for communication) into a single integrated system with a common optical path. The signal combiner merges the two laser outputs, allowing them to share the same transmission medium and optical components, thereby reducing overall system complexity despite the addition of the plasma generation capability
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 increases the bit rate and extends communication range, maintaining signal integrity despite changes in the medium, such as flow, turbulence, and particulates, and exhibits robustness against air turbulence and refractive index gradients, resulting in a 5-12% increase in received signal amplitude.
Implementation Method 1
a first laser to generate a laser-induced plasma filament within an optically-transparent medium
Implementation Method 2
The index of refraction of an optically transparent media is affected by the presence of an intense electromagnetic field associated with the laser beam
Implementation Method 3
self-focusing due to optical Kerr effect and optical diffraction
Implementation Method 4
self-focusing due to optical Kerr effect and optical diffraction
Implementation Method 5
acts as a low-loss conduit for a communication laser beam, allowing it to propagate through adverse conditions
Data Source
AI summary
A system and method involve using a first laser to generate a laser-induced plasma filament within an optically-transparent medium, using a second laser to generate a communication signal, and using a signal combiner positioned within the path of both the first laser and the second laser to direct the communication signal through the laser-induced plasma filament to a receiver located within the optically-transparent medium.