Pulsed Light Generator Gain Control via Pump Laser Pulse Width
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Solution Overview
Problem
High power pulsed light generation devices experience power fluctuations and instability in the transient period when switching from an OFF state to an ON state, leading to reduced operational efficiency and processing quality in laser processing due to uncontrolled gain fluctuations in the optical amplifier.
Innovation Solution
A high power pulsed light generation device that controls the pulse width of the pulsed driving current to synchronize with a master clock signal, using Pulse Width Modulation (PWM) to adjust the gain of the optical amplifier for each pulse, thereby stabilizing the peak power output and minimizing transient phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shunt type constant current driving circuit is used to control the pump LD output to be constant, then the output current is optimized for time periods from 1 sec to 1 hr, but the response time of the driving circuit becomes 1 msec or greater and it is difficult to turn on and turn off output light at high speed
Solution Approach 1:
The patent changes the driving mode of the pump LD from constant current control to pulse width modulation (PWM) control. By changing the parameter of driving current from DC to pulsed waveform and controlling the duty cycle, the system achieves high-speed response while maintaining output stability through synchronized pulsing with the optical oscillator.
Solution Approach 2:
The patent applies periodic pulsed driving to the pump LD, where the driving current is supplied in synchronized pulses with the optical oscillator. This periodic action enables high-speed switching capability while maintaining stable output through consistent pulse timing and width control.
2Reliability
If the pulse width of pulsed light for pumping is not controlled in the transient period, then the gain of optical amplifier fluctuates and peak power of output pulsed light becomes unstable, but controlling pulse width requires additional control mechanisms
Solution Approach 1:
The patent incorporates feedback control where the control unit monitors the operating state of the optical amplifier and adjusts the pulse width of the driving current accordingly. During the transient period, the system detects gain fluctuations and automatically corrects them by modulating the pump LD pulse width, ensuring stable peak power output.
Solution Approach 2:
The patent applies preliminary action by controlling the pulse width of the pump LD during the transient period before the optical amplifier reaches steady state. The control unit anticipates gain fluctuations and pre-adjusts the pumping pulse width to maintain stable output power from the beginning of operation.
3Manufacturing precision
If the device operates in transient period after switching from OFF to ON state, then power fluctuations occur reducing processing quality, but extending standby period reduces operational efficiency
Solution Approach 1:
The patent applies dynamics by making the pulse width of the pump LD controllable and adaptable in real-time. During the transient period, the system dynamically adjusts the pumping pulse width based on the optical amplifier's operating state, enabling stable operation throughout the transient period and eliminating the need for extended standby periods.
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 solution stabilizes the peak power of the output pulsed light immediately after state changes, reducing the standby period and enhancing the flexibility and efficiency of laser processing by controlling the gain of the optical amplifier for each pulse.
Implementation Method 1
a pulsed light source that generates a pulsed light and an optical amplifier that amplifies the pulsed light emitted from the pulsed light source to output a high power pulsed light, wherein the pulsed light source uses a semiconductor laser
Implementation Method 2
an optical amplifier that amplifies the pulsed light emitted from the pulsed light source to output a high power pulsed light
Data Source
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AI summary
A high power pulsed light generation device includes: a master clock generator that generates a master signal; an optical oscillator that generates a pulsed light synchronized with the master clock signal; an optical amplifier that amplifies the pulsed light emitted from the optical oscillator to output a high power pulsed light; a pump semiconductor laser that generates a pulsed light for pumping the optical amplifier; a driving unit that drives the pump semiconductor laser by a pulsed driving current synchronized with the master clock signal; and a control unit which controls the driving unit and controls a gain of the optical amplifier for each pulse by changing a pulse width of the pulsed drive current from driving unit so as to change the pulse width of the pumping pulsed light.