Laser Amplifier ASE Oscillation Control via Feedback
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Solution Overview
Problem
Laser devices with amplifiers can experience abnormal oscillations due to reflected high-intensity light, potentially damaging the light source, as existing systems do not effectively isolate all reflected light, leading to potential damage from re-input ASE.
Innovation Solution
A laser device that monitors the intensity of light between the light source and amplifier, using a pumping controller to adjust the pumped state of the amplification medium, reducing stimulated emission and preventing abnormal oscillations by controlling the pumping unit when high ASE intensity is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the amplification medium is pumped to high level to increase amplification capability, then the amplification efficiency is improved, but abnormal oscillations may occur due to reflected ASE being re-input to the amplifier
Solution Approach 1:
The patent implements a feedback control mechanism where a monitor unit detects the intensity of light output from the amplifier toward the light source (including ASE). When the detected intensity exceeds a predetermined threshold, the system feeds back a signal to the pumping controller to lower the pumped state level of the amplification medium, thereby preventing abnormal oscillations while maintaining efficient amplification during normal operation.
Solution Approach 2:
The patent employs preliminary action by proactively monitoring the light intensity from the amplifier output before abnormal oscillations can develop. The monitor unit continuously detects ASE intensity, and when threshold exceedance is detected, the pumping controller preemptively adjusts the pumped state level downward, preventing the harmful feedback loop from establishing rather than reacting after damage occurs.
2Loss of information
If reflected light is monitored at the output terminal to detect processing conditions, then the monitoring function is achieved, but reflected light may still reach the light source and cause abnormal oscillations
Solution Approach 1:
The patent segments the optical path into distinct monitoring and amplification sections. The monitor unit is positioned to detect only the light output from the amplifier toward the light source, separating this monitoring function from the main amplification path. This segmentation allows independent control and detection without interfering with the primary laser operation, enabling simultaneous information gathering and harm prevention.
Solution Approach 2:
The monitor unit serves as an intermediary device that intercepts and detects the light traveling from the amplifier toward the light source before it can cause damage. This intermediary detection mechanism provides early warning of high ASE intensity conditions, enabling the pumping controller to adjust the pumped state level and prevent abnormal oscillations from developing.
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
Prevents abnormal oscillations in the amplifier by detecting and managing the intensity of ASE re-input, ensuring the pumped state is maintained within safe limits, thereby protecting the light source from damage.
Implementation Method 1
an amplifier that amplifies light to be amplified with a pumped amplification medium
Implementation Method 2
the pumped amplification medium then emits spontaneous emission light
Implementation Method 3
ASE (Amplified Spontaneous Emission), which is obtained by amplifying the spontaneous emission light, is output from the amplifier
Data Source
Figure 1~2
Figure 3
AI summary
A laser device that can prevent abnormal oscillations in the amplifier is provided. The laser device includes: a seed light source (10) that outputs seed light; a pumping light source (20) ; an amplification optical fiber (30) as the amplifier that amplifies the seed light with an element pumped by the pumping light source (20) ; a monitor unit (50) that is provided between the seed light source (10) and the amplification optical fiber (30), and monitors the intensity of the light output from the amplification optical fiber (30); and a light source controller (61) that controls the seed light source (10). In this laser device, when the light input to the monitor unit (50) has an intensity equal to or higher than a predetermined intensity while the seed light is not input to the amplification optical fiber (30), the light source controller (61) forces to output the seed light from the seed light source (10).