Laser Back-Reflection Detection via Adjustable Reflector
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Solution Overview
Problem
Semiconductor lasers experience power loss and potential chip damage due to back-reflection light, which affects the quality of the laser beam and can lead to device failure, and existing methods fail to effectively detect and manage this issue.
Innovation Solution
A method involving the splitting of input light into detection light and back-reflection light, using optical power meters and an adjustable reflector to establish a power relationship, and rotating the reflector to assess different reflection angles, with a detection device comprising a dual-channel optical coupler, power meters, and a processor to calculate and monitor back-reflection light power relative to input light power, triggering an alarm if exceeding a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If back-reflection light is not detected and managed, then the laser device operates without monitoring, but the laser power decreases and chip damage occurs
Solution Approach 1:
The input light is segmented into multiple paths using optical couplers: one path directs light to the laser, another path directs it to the adjustable reflector for back-reflection simulation, and a third path directs it to the optical power meter for detection. This segmentation allows simultaneous operation and monitoring without interfering with the main laser function.
Solution Approach 2:
An adjustable reflector is introduced as an intermediary component to simulate back-reflection light. The reflector redirects a portion of the input light to create controlled back-reflection conditions, allowing the detection system to monitor potential damage conditions without exposing the actual laser chip to harmful reflection levels.
2Measurement precision
If the adjustable reflector is rotated to multiple angles, then comprehensive back-reflection detection is achieved, but the detection time increases
Solution Approach 1:
The adjustable reflector is rotated through multiple predetermined angles in a periodic sequence, with each angle position holding steady long enough for the optical power meter to complete its measurement. This periodic action ensures comprehensive detection at different reflection angles while maintaining efficient measurement cycles.
Solution Approach 2:
Multiple angle positions for the adjustable reflector are predetermined and programmed before the detection process begins. The system prepares the sequence of angle positions in advance, allowing the reflector to automatically transition through predetermined angles without real-time calculation or adjustment delays.
3Measurement precision
If the optical power meter measures input light power, then the power relationship can be established, but the direct measurement of back-reflection light is not obtained
Solution Approach 1:
Instead of directly measuring the back-reflection light that would require complex optical arrangements, the system creates a copy of the input light path using the adjustable reflector. By measuring the input light power with the optical power meter and using the known reflector angle, the system calculates the back-reflection light power through established optical relationships, avoiding direct measurement difficulties.
Solution Approach 2:
The system replaces direct optical measurement of back-reflection light with a calculation-based approach. By measuring the input light power electrically with the optical power meter and applying mathematical relationships based on reflector angle and optical coupling ratios, the system substitutes complex optical measurement with simpler electrical measurement and computation.
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
Effectively detects and manages back-reflection light power in semiconductor lasers, preventing damage and maintaining beam quality by establishing a corresponding power relationship and alerting for excessive back-reflection, thus ensuring the longevity and performance of the laser device.
Implementation Method 1
a dual-channel optical coupler, configured to separate laser input light into first detection light and second detection light
Implementation Method 2
where a part of the second detection light reflected by the adjustable reflector is obtained
Implementation Method 3
detecting the power of the first detection light by using the first optical power meter, and detecting the power of the second back-reflection light by using a second optical power meter
Data Source
AI summary
The present invention discloses a method for detecting influence on a laser from back-reflected light of the laser and a detection device. The method includes: receiving laser light input by a laser; splitting the input light into first detection light and second detection light via a beam coupler having a specific distribution proportion, and outputting the first detection light and the second detection light to a first optical power meter and an adjustable reflector, respectively; receiving a part of the second detection light reflected by the adjustable reflector, splitting the part of the second detection light reflected by the adjustable reflector into first back-reflection light and second back-reflection light, and returning the first back-reflection light and the second back-reflection light to the laser and the first optical power meter, respectively, detecting power of the first detection light by using the first optical power meter, and detecting power of the second back-reflection light by using a second optical power meter, and calculating power of the input light of the laser and power of the first back-reflection light, and establishing a power corresponding relationship between the power of the first back-reflection light and the power of the input light of the laser. By means of the foregoing manner, the present invention can detect a corresponding relationship between power of back-reflection light and power of input light of a laser.