Arbitrary Waveform Generator for Laser Diode Driver Overshoot Reduction
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Solution Overview
Problem
Conventional methods for controlling high average power diode-pumped solid state lasers are ineffective in achieving precise control of individual laser diodes and large arrays, leading to inefficiencies and potential premature failure due to current variations and latency issues, especially in applications like Inertial Fusion Engines where synchronized operation is critical.
Innovation Solution
A system utilizing an arbitrary waveform generator and self-correcting feedback mechanisms to dynamically control the current applied to laser diodes, allowing for precise and flexible operation by actively sensing and adjusting the current flow, thereby preventing overshoot and undershoot, and ensuring uniform output from each diode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional control methods are used for laser diodes, then the control system is simple, but the control precision and reliability deteriorate due to current variations and latency issues
Solution Approach 1:
The patent implements a feedback mechanism where the actual current flowing through the laser diode is measured and compared with the desired current value. A beam control unit receives information about the actual current and generates a corrected current pulse to compensate for deviations, thereby improving control precision through closed-loop feedback control
Solution Approach 2:
The system pre-calculates and stores correction factors based on the relationship between desired and actual current values. When a current pulse is needed, the system retrieves the pre-computed correction data to quickly generate the appropriate corrected current pulse, reducing latency without sacrificing precision
2Reliability
If conventional current control is applied to laser diodes, then the system operates continuously, but current overshoot and undershoot occur causing stress and reducing lifespan
Solution Approach 1:
The feedback mechanism continuously monitors the actual current and compares it with the desired current value. When the actual current deviates from the desired value, the beam control unit generates a corrected current pulse to bring the current back to the target level, preventing excessive overshoot and undershoot that would cause stress
Solution Approach 2:
The system applies preliminary correction by pre-calculating the appropriate current pulse amplitude based on the measured relationship between desired and actual current. This preliminary adjustment compensates for system imperfections before the current pulse is applied, preventing harmful overshoot and undershoot conditions
3Reliability
If precise current control is implemented with feedback mechanisms, then control accuracy and reliability improve, but the device complexity increases due to additional sensing and control circuitry
Solution Approach 1:
The patent employs a feedback control system where a sensing device measures the actual current and feeds this information back to the beam control unit, which adjusts subsequent current pulses to maintain accurate control, thereby improving reliability through intelligent regulation
Solution Approach 2:
The system performs self-correction by automatically adjusting current pulses based on feedback from the sensing device. The beam control unit independently determines the appropriate correction and generates the corrected current pulse without external intervention, enabling the system to self-regulate and maintain high reliability
Data Source
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AI summary
An arbitrary waveform generator modifies the input signal to a laser diode driver circuit in order to reduce the overshoot/undershoot and provide a "flat-top" signal to the laser diode driver circuit. The input signal is modified based on the original received signal and the feedback from the laser diode by measuring the actual current flowing in the laser diode after the original signal is applied to the laser diode.