Picosecond Laser Diode With External Reflector Feedback

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional short-pulse lasers, such as picosecond lasers, face challenges with low pulse energy, unstable output due to ambient temperature fluctuations, and high costs associated with short-pulse circuit drivers, while nanosecond lasers produce rough burrs and unsatisfactory stripping quality.

Innovation Solution

An apparatus generating a short-pulse laser using a temporally modulated sideband gain, incorporating an external reflector with a laser diode, achieves a picosecond pulse width of 100 ps and adjustable repetition rate, employing a pulse driver modulator, wavelength filter, and optical fiber components to stabilize and enhance laser output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If gain-switched diode is used to generate picosecond laser, then pulse width is reduced to picosecond scale, but pulse energy becomes too low (several pico-joules) and second peak pulse tail is produced

Engineering Contradiction:

Improvepulse widthVSAvoidpulse energy

Core Design Contradiction:

Duration of action of moving objectVSUse of energy by moving object

Solution Approach 1:

The patent combines gain-switched diode with external optical feedback to merge the advantages of short pulse width generation with sufficient pulse energy. The external reflector provides feedback that shapes the pulse while maintaining high energy levels, eliminating the low energy problem of conventional gain-switched diodes.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces an external reflector as an intermediary component between the gain-switched diode and the output. This reflector mediates the pulse formation process, enabling the system to achieve both picosecond pulse width and high pulse energy by controlling the feedback timing and intensity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If direct diode technique is used, then optical efficiency and temperature control are improved, but short-pulse circuit driver cost becomes extremely high

Engineering Contradiction:

Improveoptical efficiencyVSAvoiddriver circuit cost

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent enables the laser diode to self-generate picosecond pulses through external optical feedback, eliminating the need for complex short-pulse circuit drivers. The optical feedback mechanism allows the system to self-organize into picosecond pulses without expensive electronic pulse shaping circuits.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces electronic pulse shaping circuits with an optical feedback mechanism. Instead of using complex electronic drivers to shape the pulse, the system uses optical reflection and feedback to naturally form picosecond pulses, significantly reducing driver circuit complexity and cost.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Duration of action of moving object

If DPPS laser microchip is used, then picosecond pulse is generated, but pulse width is slightly too large (above 500 picoseconds)

Engineering Contradiction:

Improvepulse widthVSAvoidpulse width precision

Core Design Contradiction:

Duration of action of moving objectVSManufacturing precision

Solution Approach 1:

The patent changes the key parameter of feedback timing by adjusting the external reflector distance and optical path length. This parameter change enables the system to achieve picosecond pulse widths below 500 ps, overcoming the limitation of DPPS laser microchips which produce pulses above 500 ps.

Inventive Principle:

Principle #35Parameter changes

4Use of energy by moving object

If nanosecond laser is used, then pulse energy is sufficient, but processing quality becomes poor with rough burrs and unsatisfactory stripping quality

Engineering Contradiction:

Improvepulse energyVSAvoidprocessing quality

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent uses periodic optical feedback from the external reflector to create a sequence of gain and loss events within the laser cavity. This periodic action shapes the pulse into a clean picosecond waveform with sufficient energy, eliminating the rough burrs associated with nanosecond pulses while maintaining processing quality.

Inventive Principle:

Principle #19Periodic 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 apparatus provides high energy stability and improved processing effects for material and biomedical applications, offering a more efficient and cost-effective solution compared to nanosecond and continuous beams with similar average power.

Implementation Method 1

an external reflector is added to cooperate with a laser diode

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

The wavelength filter blocks a long-pulse laser signal having a first wavelength pulse, and outputs a single short-pulse laser signal having a second wavelength picosecond short pulse

Methodology Applied

Scientific EffectWavelength filtering: Filter (optical)

Data Source

PatentUS8831052B2Apparatus for generating short-pulse laser using temporally modulated sideband gain

Publication Date: 2014.09.09 IND TECH RES INST

AI summary

An apparatus for generating a short-pulse laser using a temporally modulated sideband gain is provided. The apparatus includes a laser diode and an external reflector. By use of a time difference resulted by a nanosecond laser pulse signal at the external reflector, a sideband gain is obtained for generating a short-pulse picosecond laser output.