Multi-Channel Fiber Laser Combining High Power With Low Retropulsion
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Solution Overview
Problem
Current medical lasers, such as Ho:YAG lasers, are expensive, cumbersome, and have low wall-plug efficiency, while fiber lasers offer higher efficiency but struggle to achieve the high output power needed for certain medical procedures like lithotripsy, leading to undesirable stone fragmentation and retropulsion of fragments.
Innovation Solution
A high-power multi-channel fiber laser system with Tm-doped gain sections, combined laser outputs, and diode lasers generating optical pump pulses to achieve quasi-continuous wave laser pulses with controlled electrical pulses, delivering over 1 kW of power between 1925 nm and 2100 nm to the target.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If Ho:YAG laser is used to achieve high output power for lithotripsy, then stone fragmentation efficiency is improved, but wall-plug efficiency deteriorates and device complexity increases
Solution Approach 1:
The patent replaces the traditional lamp-pumped Ho:YAG laser system with a diode-pumped fiber laser system. This substitution uses diode lasers to pump Tm-doped optical fibers, eliminating the need for inefficient lamp pumping mechanisms and achieving both high output power and improved wall-plug efficiency simultaneously
Solution Approach 2:
The patent changes the lasing wavelength from 2.1 μm (Ho:YAG) to 1.9-2.0 μm (Tm-doped fiber laser). This parameter change allows the system to achieve comparable or superior stone fragmentation efficiency while improving wall-plug efficiency and reducing device complexity
2Productivity
If high-power laser pulses are used to achieve fast stone ablation, then productivity is improved, but harmful factors increase due to retropulsion and large fragment formation
Solution Approach 1:
The patent uses pulsed laser operation with carefully controlled pulse duration and repetition rate. By delivering energy in periodic pulses rather than continuous wave, the system achieves fast stone ablation while allowing thermal diffusion between pulses, preventing excessive steam generation and retropulsion
Solution Approach 2:
The patent dynamically adjusts laser parameters including pulse duration, repetition rate, and peak power based on real-time treatment conditions. This dynamic control allows optimization of ablation efficiency while minimizing harmful retropulsion effects throughout the procedure
3Productivity
If high-power laser pulses are used to achieve fast stone ablation, then productivity is improved, but harmful factors increase due to large fragment formation
Solution Approach 1:
The pulsed laser delivery system allows precise control over energy deposition timing. By using appropriate pulse durations and repetition rates, the system achieves efficient ablation while promoting formation of smaller fragments through controlled thermal stress and steam explosion mechanisms
Solution Approach 2:
The patent changes laser parameters including wavelength (1.9-2.0 μm), pulse duration, and peak power to optimize fragmentation characteristics. These parameter changes enable fast ablation while producing smaller, more easily removable stone fragments
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 system effectively disintegrates kidney stones with reduced retropulsion and large fragment formation, maintaining fiber laser longevity by managing power within safe thresholds, enabling efficient and controlled stone fragmentation.
Implementation Method 1
one or more diode lasers configured for providing optical pump pulses to the plurality of fiber laser amplifiers, wherein the laser light outputs from the plurality of fiber laser amplifiers are generated in response to the provided optical pump pulses
Implementation Method 2
one or more diode lasers configured for providing optical pump pulses to the plurality of fiber laser amplifiers
Implementation Method 3
an optical delivery fiber configured to receive the combined output from the plurality of laser amplifiers into the delivery fiber and configured to deliver the combined output to a target
Implementation Method 4
the fiber laser amplifiers each include a Tm-doped gain section
Implementation Method 5
the laser light outputs from the plurality of fiber laser amplifiers are generated in response to the provided optical pump pulses
Data Source
AI summary
The techniques described herein relate to a laser system, including: a plurality of fiber laser amplifiers; a beam combiner configured to combine laser light outputs from the plurality of fiber laser amplifiers; an optical delivery fiber configured to receive the combined output from the plurality of laser amplifiers into the delivery fiber and configured to deliver the combined output to a target; one or more diode lasers configured for providing optical pump pulses to the plurality of fiber laser amplifiers, wherein the laser light outputs from the plurality of fiber laser amplifiers are generated in response to the provided optical pump pulses.