Unstabilized Laser Diode Fiber Amplifier Wavelength Compensation
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Solution Overview
Problem
Existing laser systems for portable or handheld devices face challenges in achieving compactness, robustness, and low power consumption while maintaining high power and accurate distance range finding and target designation, especially under environmental hazards.
Innovation Solution
A compact and robust laser system is developed using a master-oscillator/power-amplifier arrangement with an active optical fibre power-amplifier, gain modulation, and a controllably shiftable optical fibre filter to compensate for environmental effects, ensuring high power output and accurate target evaluation with reduced noise and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If temperature stabilization measures are implemented for the laser diode, then wavelength stability is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent extracts the temperature stabilization function from the laser diode system by introducing a separate optical filter with temperature-dependent spectral characteristics. The filter compensates for wavelength drift without requiring temperature control of the laser diode itself, thereby reducing device complexity while maintaining wavelength stability.
Solution Approach 2:
The optical filter acts as an intermediary element between the laser diode and the external environment. Its temperature-dependent spectral characteristics mediate the wavelength drift caused by temperature changes, allowing the system to maintain stable operation without direct temperature control of the laser diode.
2Stability of the object's composition
If temperature stabilization measures are implemented for the laser diode, then wavelength stability is improved, but power consumption increases
Solution Approach 1:
The patent removes the power-consuming temperature stabilization mechanism from the laser diode system. Instead, it uses a passive optical filter whose temperature-dependent characteristics automatically compensate for wavelength drift, thereby maintaining wavelength stability without additional power consumption.
Solution Approach 2:
The optical filter performs the wavelength stabilization function autonomously by exploiting its inherent temperature-dependent spectral characteristics. As the filter temperature changes with the laser diode, it automatically adjusts its transmission characteristics to compensate for wavelength drift, eliminating the need for active temperature control and associated power consumption.
3Volume of moving object
If compact design is implemented using all optical fibre components, then device size is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent employs standard optical fibre components (circulator, optical filter, active fibre amplifier) that can be manufactured using conventional techniques and then integrated into a compact all-fibre configuration. This multi-functional approach allows each component to perform its standard function while contributing to the overall compact design, balancing manufacturing ease with size reduction.
4Power
If high power output is achieved using active optical fibre amplifier, then laser power is improved, but noise increases
Solution Approach 1:
The patent uses the temperature-dependent spectral characteristics of the optical filter as a form of passive feedback. As the amplifier and filter temperatures change, the filter's transmission characteristics automatically adjust to compensate for wavelength drift and reduce noise, maintaining high power output without significant noise increase.
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
The system achieves high power output with improved accuracy and reduced noise, maintaining compactness and low power consumption, suitable for handheld devices and various environmental conditions.
Implementation Method 1
downstream of a laser source there is provided an optical fibre filter which has spectral characteristics shiftable in dependency of a temperature
Implementation Method 2
the laser system comprises an active optical fibre power-amplifier which has an input and an output
Implementation Method 3
Latter comprises a circulator with an input, with an output and with an output/input
Data Source
AI summary
A laser system has an output/input coupler unit (49) with a circulator (37). An output of the circulator (37) is operationally connected to a detector unit (43). The input/output (EA37) of the circulator is operationally connected to a transmitter and a receiver optics 41. Laser light is input to the circulator (E37). The input (E37), output (A37) and output/input (EA37) of the circulator are optical fibers. The pulsed diode (3) is not temperature stabilized. To reduce amplified spontaneous emission (ASE) generated in the optical fiber amplifier (9), a narrow band-pass filter unit (29) is used. Filter unit (29) has a central wavelength with a temperature dependence which is matched to the temperature dependent wavelength shift of the pulsed diode (3).