Fiber Laser Rangefinding Beyond Night Vision Detection
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Solution Overview
Problem
Current laser rangefinders are limited by their wavelength range, particularly those using laser light within the 1530 nm to 1610 nm bandwidth, which reduces their applicability and is visible to night vision devices and imaging sensors, limiting their effectiveness in certain applications.
Innovation Solution
The use of a thulium and/or holmium doped fiber laser with a wavelength range of 1900 nm to 2150 nm, combined with Bragg gratings and a pumping laser, allows for invisible operation to current night vision devices and imaging sensors, providing high-efficiency and robust distance measurement capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If laser light within the 1530 nm to 1610 nm bandwidth is used, then the laser rangefinder can operate with available laser technology, but it becomes visible to night vision devices and imaging sensors, reducing effectiveness in certain applications
Solution Approach 1:
The patent changes the wavelength parameter of the laser light from the conventional 1530-1610 nm range to the 1900-2150 nm range. This parameter change makes the laser invisible to current night vision devices and imaging sensors while maintaining effective distance measurement capability, thus resolving the contradiction between adaptability and detectability
2Object-affected harmful factors
If a thulium and/or holmium doped fiber laser with wavelength range of 1900 nm to 2150 nm is used, then the laser becomes invisible to night vision devices and imaging sensors, but the device complexity increases due to the need for Bragg gratings and pumping laser
Solution Approach 1:
The patent employs a nested structure where the thulium and/or holmium doped fiber section is integrated within the fiber laser system, with Bragg gratings embedded in the fiber structure and the pumping laser coupled to the doped fiber section. This nesting approach consolidates multiple components into a compact integrated system, managing the complexity while achieving the desired wavelength output
3Measurement precision
If pulsed operation is used to achieve sufficiently strong signal intensities, then the measurement accuracy is improved, but the device complexity increases due to pulse modulation requirements
Solution Approach 1:
The patent employs periodic pulsed operation of the laser, where short laser pulses are emitted at regular intervals. This periodic action allows the use of time-of-flight measurement techniques, where the distance is calculated based on the time for light to travel to the target and back. The pulsed operation improves measurement precision by providing distinct temporal markers for distance calculation, while the simplicity of pulse generation and detection manages the overall device complexity
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 configuration enhances the applicability and accuracy of distance measurements by operating within a wavelength range that is not detectable by current night vision devices, offering improved signal-to-noise ratio and robustness against mechanical perturbations, while maintaining stability across varying temperatures.
Implementation Method 1
a thulium and/or holmium doped fiber laser with a thulium and/or holmium doped fiber section, two Bragg gratings arranged on both sides of the thulium and/or holmium doped fiber section
Implementation Method 2
two Bragg gratings arranged on both sides of the thulium and/or holmium doped fiber section
Implementation Method 3
a pumping laser and a thulium and/or holmium doped fiber laser with a thulium and/or holmium doped fiber section
Implementation Method 4
The distance between the device and the target object can be determined with knowledge of the propagation speed of the optical signal and on the basis of the determined travel time between emission and reception of the signal
Data Source
AI summary
The inventive Device is comprising a laser rangefinder for determining the distance along a laser axis between the device and a target object. The laser rangefinder is comprising a pumping laser and a thulium and/or holmium doped fiber laser with a thulium and/or holmium doped fiber section and two Bragg gratings arranged on both sides of the thulium and/or holmium doped fiber section of the thulium and/or holmium doped fiber laser wherein the thulium and/or holmium doped fiber laser is pumped by the pumping laser and configured to emit laser light with a wavelength in the range of 1900 nm to 2150 nm. The inventive device has an improved applicability.