Electro-optical Laser Pulse Modulation Voltage Converter

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Solution Overview

Problem

Existing systems for modulating laser pulses in ultra-short pulse laser systems face challenges due to long switching times in high-voltage switches, leading to erroneous modulations and impaired processing results, especially in femtosecond lasers with high repetition rates.

Innovation Solution

A voltage converter is used upstream of the electro-optical modulator to convert a pulsed switching voltage from a low output voltage level to a higher modulation voltage level, while maintaining the pulse sequence, allowing for shorter switching times and reducing the risk of erroneous modulations. This configuration includes a transformer or step-up converter and a semiconductor pulse generator, such as a transistor switch, to achieve precise modulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a high-voltage switch is used to generate pulsed modulation voltage directly, then the modulation voltage can be generated at the required high voltage level, but the switching time becomes excessively long, leading to erroneous modulations in ultra-short pulse laser systems

Engineering Contradiction:
Improvemodulation voltage levelVSAvoidswitching time
Core Design Contradiction:
PowerVSLoss of time

Solution Approach 1:

The voltage generation process is divided into two separate stages: first generating a pulsed voltage at low voltage level with fast switching, then transforming it to the required high voltage level. This segmentation allows each stage to be optimized independently - the low-voltage stage for fast switching and the transformation stage for voltage level adjustment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A low-voltage pulsed signal serves as an intermediary between the control signal and the final high-voltage modulation signal. The low-voltage pulse generator creates a fast-rising pulse that is then transformed by the voltage converter to achieve the required high voltage level while maintaining the fast rise time characteristic.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the rise time of modulation voltage is reduced to match ultra-short pulse laser systems, then precise pulse-to-pulse modulation becomes possible, but the system complexity increases due to the need for fast high-voltage switching

Engineering Contradiction:
Improvemodulation precisionVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system replaces direct mechanical/electrical high-voltage switching with an electromagnetic transformation approach. Instead of using a high-voltage switch that mechanically or electronically switches at high voltage, the invention uses a voltage converter (transformer) that electromagnetically transforms a low-voltage pulse to high voltage, achieving the same result with simpler and faster components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If high-voltage switches are used in ultra-short pulse laser systems with high repetition rates, then the laser pulses can be modulated, but the long rise times cause erroneous modulations and impair processing results

Engineering Contradiction:
Improvelaser pulse modulation capabilityVSAvoidmodulation accuracy
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The low-voltage pulsed signal is generated in advance with the correct pulse timing and sequence, before being transformed to high voltage. This preliminary generation of the pulse pattern at low voltage ensures that the timing and synchronization are established before the voltage transformation, preventing any timing errors or erroneous modulations.

Inventive Principle:
Principle #10Preliminary action

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 solution significantly reduces the risk of erroneous modulations by achieving shorter rise times for the modulation voltage, allowing for precise pulse-to-pulse variation and accurate modulation of laser pulses, even in ultra-short pulse laser systems, thereby improving processing and measurement precision.

Implementation Method 1

a voltage converter (12) connected upstream of the modulator (4), which converts a pulsed switching voltage (13) at an output voltage level into the modulation voltage (5), which is increased compared to the output voltage level

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

electro-optical modulators such as Pockels cells are provided as modulators, to which an electrical modulation voltage is applied on the input side and enable optical modulation of the laser pulses in phase, polarization or intensity on the output side

Methodology Applied
Scientific EffectPockels effect: Pockels Effect

Data Source

PatentEP3183783B1System and method of modulating laser pulses
Publication Date: 2020.12.23 AMPHOS
  • EP3183783B1 patent drawingFigure 1~2d
  • EP3183783B1 patent drawingFigure 3~4d
  • EP3183783B1 patent drawingFigure 5~6c

AI summary

The present invention relates to a system for modulating laser pulses (3) by means of an electro-optical modulator (4) which is operated by means of a pulsed modulation voltage (5). A voltage converter (12) mounted upstream of the modulator (4) converts a pulsed modulated switching voltage (13) at an output voltage level to the modulation voltage (5) that is higher than the output voltage level. The invention further relates to a method for modulating laser pulses (3).