Laser Driver Wave Shaping for Relaxation Oscillation Suppression
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Solution Overview
Problem
Existing laser devices experience fiber burnout due to large relaxation oscillations at the beginning of the pulse, which result in abnormal power surges exceeding the rated power of the optical fiber.
Innovation Solution
A wave shaping circuit for laser driving circuits is introduced, comprising a signal input interface, trigger starting unit, delayed power supply control unit, delay unit, attenuation control unit, constant voltage control unit, signal coupling unit, and signal output interface. This circuit attenuates the input signal at the start of the pulse to reduce power and then outputs the original pulse power after a delay, minimizing relaxation oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high power pulse signals are directly applied to laser devices, then high power output is achieved, but relaxation oscillations cause fiber burnout
Solution Approach 1:
The wave shaping circuit performs preliminary action by attenuating the leading edge of the pulse signal before it reaches the laser device. The attenuation control unit reduces the amplitude of the rising edge portion of the input signal, preventing excessive current from reaching the laser diode at the start of the pulse, thereby avoiding fiber burnout while maintaining high power output capability
Solution Approach 2:
The circuit changes the temporal parameter of the pulse signal by modifying its waveform shape. The wave shaping circuit transforms the original square wave pulse into a pulse with a controlled rising edge, delaying and attenuating the initial power surge. This parameter change ensures the signal rises gradually, preventing relaxation oscillations while preserving the overall pulse energy and high power output
2Power
If pulse signals with high current are applied, then high power laser output is achieved, but abnormal power surges exceed fiber rated power
Solution Approach 1:
The wave shaping circuit provides beforehand cushioning by introducing a controlled attenuation phase at the beginning of the pulse. The attenuation control unit acts as a cushion that absorbs and limits the initial power surge, preventing it from exceeding the fiber's rated power. This cushioning effect occurs before the full power signal reaches the laser device, protecting the fiber from damage
Data Source
AI summary
The present application provides a wave shaping circuit of a laser driving circuit, a laser driving circuit and a laser device, by attenuating the wave at the start of the pulse to a lower power, and then outputting the original pulse power after a delay, the laser relaxation oscillations disappears or occurs at a lower power of the light emission, with which the amplitude and probability of generation of the relaxation oscillations are reduced, thereby reducing the abnormal power at the moment of pulse operation and preventing the optical fiber from being overheated and damaged.