Electro-Optical Modulator Light Pulse Generation

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Solution Overview

Problem

Current systems for generating short or ultrashort light pulses are limited by their complexity, sensitivity to environmental variations, and difficulty in tuning pulse duration, repetition frequency, and wavelength, particularly in fiber laser systems which suffer from nonlinear optical effects and chromatic dispersion.

Innovation Solution

A system that generates light pulses without a resonant laser cavity or mode locking, using an electrical generator to produce analog electrical modulation signals that can tune the duration and frequency of light pulses, and an electro-optical modulator to optically amplitude modulate continuous light radiation, allowing for wide tunability in pulse duration, repetition rate, and wavelength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If fiber laser systems are used to generate short or ultrashort light pulses, then compactness and integration are improved, but nonlinear optical effects and chromatic dispersion limit the energy and wavelength tunability

Engineering Contradiction:
Improvesystem integrationVSAvoidnonlinear optical effects
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the light pulse generation function from the fiber laser cavity structure by using an external electro-optical modulator to impose intensity modulation on continuous or long-pulse laser radiation. This separates the pulse generation mechanism from the laser medium, eliminating the harmful nonlinear effects and chromatic dispersion that occur when light is confined within the fiber cavity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an electro-optical modulator as an intermediary device between the laser source and the output. This modulator acts as a mediator that converts electrical modulation signals into optical intensity variations, enabling precise control of pulse duration and repetition frequency without the light passing through the modulator's nonlinear regime, thus avoiding harmful nonlinear optical effects.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Duration of action of moving object

If mode locking techniques are used to generate ultrashort light pulses, then pulse duration is reduced, but device complexity and sensitivity to environmental variations increase

Engineering Contradiction:
Improvepulse durationVSAvoidcavity structure
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The patent removes the resonant cavity and mode locking mechanisms from the system. Instead of using complex active or passive mode locking techniques that require precise phase alignment of multiple longitudinal modes, the invention extracts the pulse generation function by applying external intensity modulation to continuous or long-pulse laser radiation, greatly simplifying the device architecture.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/optical mode locking system with an electrical control system. An electro-optical modulator controlled by electrical signals generates the ultrashort pulses, substituting the complex optical feedback and phase alignment requirements of mode locking with straightforward electrical modulation, thereby reducing sensitivity to environmental variations.

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

3Volume of moving object

If optical fibers with small volume are used to confine light pulses, then integration is improved, but nonlinear optical effects limit the energy and peak power

Engineering Contradiction:
Improvefiber core volumeVSAvoidpeak power
Core Design Contradiction:
Volume of moving objectVSPower

Solution Approach 1:

The patent extracts the light pulses from the confined fiber core environment by using an external modulator. The laser radiation passes through the fiber only for delivery to the modulator, not for pulse generation. This allows the use of high peak power pulses without the nonlinear optical effects that would occur if the same pulses were confined within the small fiber core volume during generation.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If chromatic dispersion in optical fibers is present, then wavelength tunability is limited, but fiber laser operation is maintained

Engineering Contradiction:
Improvelaser operation stabilityVSAvoidwavelength tunability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent extracts the pulse generation process from the dispersive fiber medium. By using an external electro-optical modulator to generate pulses from continuous or long-pulse laser radiation, the system avoids the chromatic dispersion that would otherwise limit wavelength tunability. The modulator operates independently of the fiber's dispersion characteristics, allowing free wavelength selection from the laser source.

Inventive Principle:
Principle #2Taking out (Extraction)

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 approach results in a compact, easily tunable, and stable light source capable of producing high signal-to-noise ratio light pulses with adjustable duration and frequency, overcoming the limitations of existing technologies by eliminating the need for complex resonant cavities and external modulators.

Implementation Method 1

an electro-optical modulator to optically amplitude modulate continuous light radiation as a function of the electrical signal modulation and to generate modulated light radiation comprising at least one light pulse

Methodology Applied
Scientific EffectElectro-optical modulation: Electro-Optic Effects

Data Source

PatentEP3488290B1System for generating brief or ultra-brief light pulses
Publication Date: 2021.08.18 IRISIOME
  • EP3488290B1 patent drawingFigure 1~4
  • EP3488290B1 patent drawingFigure 5~8

AI summary

The invention relates to a system for generating brief or ultra-brief light pulses. According to the invention, the system comprises a light source (2) configured to emit temporally continuous-wave light radiation (20), an electrical generator (5) configured to operate at a tunable frequency in a passband comprised between 5 and 100 GHz and to emit an analogue modulating electrical signal (50) comprising at least one electrical pulse of duration comprised between 10 ps and 100 ps, and an electro-optical modulator (4) having electrodes and an electrical passband that are suitable for receiving the analogue modulating electrical signal (50), the electro-optical modulator (4) being configured to optically amplitude modulate the continuous-wave light radiation depending on the analogue modulating electrical signal and to generate modulated light radiation (40) comprising at least one light pulse of duration comprised between 10 ps and 100 ps.