Hybrid Laser Idler Wavelength Control for Constant-Energy Pulses

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Solution Overview

Problem

Hybrid lasers combining fibre and solid-state amplifiers face transient optical phenomena due to differing gain spectra, leading to inconsistent laser pulse energies during pulse on demand operations, which is undesirable for high-speed scanning systems.

Innovation Solution

A hybrid laser system that controls the spectrum of idler pulses using adjustable optical filters or temperature adjustments to stabilize amplification across different amplifier types, ensuring constant energy pulses by employing multiple idler sources with tailored wavelengths and amplitudes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If a Ti:Sapphire laser is used to generate ultrashort high-energy pulses, then pulse duration and peak power are improved, but the laser cannot operate in continuous mode and requires complex regenerative amplification systems

Engineering Contradiction:
Improvepulse durationVSAvoidlaser system complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The patent combines two different laser technologies (fiber laser and Ti:Sapphire laser) into a single hybrid system. The fiber laser provides continuous wave operation and seed pulses, while the Ti:Sapphire laser provides ultrashort high-energy pulse generation. This merging allows the system to achieve ultrashort pulse duration with high energy while avoiding the complexity of standalone regenerative amplification systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hybrid laser system performs multiple functions: it can operate in continuous mode (inherited from fiber laser) and in pulsed mode (inherited from Ti:Sapphire laser). The system can generate both continuous waves and ultrashort pulses, providing versatility that neither laser could achieve alone.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If a Ti:Sapphire laser operates in continuous mode, then ease of operation is improved, but it cannot generate the high peak powers required for applications like optical frequency comb generation

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidpeak power
Core Design Contradiction:
Ease of operationVSPower

Solution Approach 1:

The patent merges the continuous wave capability of the fiber laser with the high peak power pulse generation capability of the Ti:Sapphire laser. The fiber laser operates continuously to provide stable seed pulses, which are then amplified and compressed by the Ti:Sapphire laser to achieve the required peak powers for optical frequency comb generation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fiber laser performs preliminary action by generating continuous wave seed pulses with good temporal and spectral properties. These pre-conditioned pulses are then fed into the Ti:Sapphire laser for further amplification and compression, enabling the system to achieve high peak powers while maintaining ease of operation.

Inventive Principle:
Principle #10Preliminary action

3Use of energy by moving object

If regenerative amplification is used to increase pulse energy, then pulse energy is improved, but the system complexity and maintenance requirements increase significantly

Engineering Contradiction:
Improvepulse energyVSAvoidamplification system complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent combines the amplification capabilities of fiber lasers with the pulse compression capabilities of Ti:Sapphire lasers. This hybrid approach achieves high pulse energy without requiring complex multi-stage regenerative amplification systems, as the fiber laser provides efficient amplification and the Ti:Sapphire laser provides compression and high peak power generation.

Inventive Principle:
Principle #5Merging (Combining)

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

Achieves consistent laser pulse energies by stabilizing amplification, making the system compact, reliable, and suitable for high-speed scanning applications.

Implementation Method 1

a fiber laser which is capable of generating and amplifying laser pulses

Methodology Applied
Scientific EffectStimulated emission: Laser

Implementation Method 2

generating and amplifying laser pulses

Methodology Applied
Scientific EffectOptical amplification: Laser

Implementation Method 3

a Ti:Sapphire laser which is capable of generating ultrashort high-energy pulses

Methodology Applied
Scientific EffectStimulated emission: Laser

Implementation Method 4

generating ultrashort high-energy pulses

Methodology Applied
Scientific EffectOptical amplification: Laser

Implementation Method 5

combining the two lasers in such a way that both lasers can be operated simultaneously

Methodology Applied
Scientific EffectOptical interference: Interference

Implementation Method 6

combining the two lasers in such a way that both lasers can be operated simultaneously

Methodology Applied
Scientific EffectOptical coherence: Coherent Light

Data Source

PatentEP4111555B1A hybrid laser for generating laser pulses on demand with constant energy and a method of generating said pulses
Publication Date: 2026.04.15 UNIVERSITY OF LJUBLJANA
  • EP4111555B1 patent drawingFigure 1~3
  • EP4111555B1 patent drawingFigure 4~6
  • EP4111555B1 patent drawing

AI summary

The present invention belongs to the field of constructional details of laser devices and laser devices for controlling intensity, frequency, duration, polarization or direction of emitted rays. The invention relates to a hybrid laser for generating laser pulses on demand, said pulses having constant energy, and to a method of generating laser pulses with constant energy using the said hybrid laser. The essence of the hybrid laser is in that it comprises at least one source of primary pulses, at least one source of idler pulses, at least two laser pulse amplifiers with different gain spectra and a pulse separator for separation of primary and idler pulses, where amplification stabilisation and thus constant energy of the primary pulses is ensured by adjusting the wavelength of the idler pulses so that the spectrum of idler pulses is moved away from the maximum of the gain of the second amplifier. Preferably the adjustment of the wavelength of the idler pulses is achieved by changing the temperature of the laser diode or by using an appropriate fibre Bragg grating to achieve the wavelength stabilization of the laser diode, or by using appropriate adjustable band pass filters in the laser resonator or with appropriate adjustable reflective elements in the laser resonator.