Laser Fiber Burn Through Prevention via Attenuation
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Solution Overview
Problem
Optical fibers used in laser systems often fail due to excessive bend radii, leading to 'burn through' and potential injury, as they are unable to handle the initial unstable and high-energy laser output effectively, causing damage to the fiber coatings and increasing the risk of catastrophic failure.
Innovation Solution
A process involving a beam attenuator, such as a beam splitter or shutter, is used to keep the laser output below operational levels initially, preventing errant energy from damaging the optical fiber, and then gradually increasing the output to operational levels after a predetermined time, thereby reducing the risk of fiber failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the laser source is switched on at full operational level, then the therapeutic energy delivery is immediate and effective, but the initial unstable high-energy output causes damage to the optical fiber coatings and leads to catastrophic fiber failure
Solution Approach 1:
The system performs preliminary stabilization of the laser output before coupling it to the optical fiber. A controller monitors the laser output during a stabilization period and only allows coupling to occur after the output reaches a stable state, preventing the initial unstable high-energy output from damaging the fiber coatings.
Solution Approach 2:
A beam attenuator or optical isolator is introduced as an intermediary component between the laser source and the optical fiber. This intermediary device filters or attenuates the initial unstable high-energy output, allowing only stable, controlled energy levels to reach the fiber and prevent catastrophic failure.
2Adaptability or versatility
If the optical fiber is bent to navigate complex anatomical pathways, then the fiber can reach difficult targets, but excessive bending causes the fiber to exceed its minimum bend radius and results in burn through and fracture
Solution Approach 1:
The system changes the energy parameter by attenuating or stabilizing the laser output power level based on the fiber's bend conditions. When the fiber is bent to navigate complex pathways, the controller adjusts the laser output parameters to reduce energy levels that would otherwise cause burn through at the bend point.
Solution Approach 2:
The system incorporates feedback mechanisms that monitor the fiber's operational conditions including bend radius and energy levels. Based on this feedback, the controller dynamically adjusts the laser output to maintain safe operating parameters, preventing burn through while allowing the fiber to maintain its bent configuration for reaching difficult targets.
3Area of stationary object
If the minimum bend radius is reduced to allow tighter routing, then the fiber can navigate more complex pathways, but the fiber becomes more susceptible to burn through and catastrophic failure
Solution Approach 1:
The system dynamically changes the laser energy parameters based on the fiber's bend radius. When the fiber is configured with a tight bend radius to navigate complex pathways, the controller automatically reduces the laser output energy levels to compensate for the increased susceptibility to burn through, allowing tight routing without catastrophic failure.
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 effectively prevents premature failure of bent optical fibers by attenuating the initial high-energy laser output, allowing the fiber to operate safely at larger bend radii and reducing the risk of damage or injury from excessive energy.
Implementation Method 1
attenuating the useful amount with the use of with a beam attenuator positioned in an optical path of said laser output between the laser source and the bent optical fiber
Implementation Method 2
the beam attenuator includes at least one of a beam absorber, a beam splitter, and a beam shutter
Implementation Method 3
attenuating the useful amount with the use of with an optical beam splitter positioned in an optical path of the laser output at 10° to 80° with respect to the optical path between the laser source and the bent optical fiber
Data Source
AI summary
Optical fibers used to deliver laser energy inside the body are often twisted and bent when passed through tortuous routes in accessing the target tissue or pathology, e.g. during the ureteroscopic laser lithotripsy. When an irregular laser output that is produced at the start of the lasing process is channeled through a fiber that is bent at or near the bend limit, fail safe polymer claddings are damaged and can no longer contain even regular laser output in tight deflection. A common resulting fiber failure, known as ‘fiber burn through’, results in injuries to patients and is a major cause of damage to ureteroscopes. Discussed are the systems and methodologies providing a solution to such premature fiber failure.